JP2008210900A - Semiconductor light emitting element and light emitting device provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device having reduced loss of light to be absorbed by a pad electrode and also improved characteristic thereof. <P>SOLUTION: In the light emitting device 30 including a semiconductor light emitting element 1 and a wavelength converting member such as a phosphorus material or the like, reflecting layers 10c, 20c are provided on the outermost surface layers of a type p pad electrode 10a and a type n pad electrode 20a provided on the same surface side of the semiconductor light emitting element 1. Accordingly, the output light L emitted from a light emitting layer 4 of the semiconductor light emitting element 1 is capable of guiding a returning light having changed the traveling direction toward the semiconductor light emitting element 1 through reflection by a phosphorus material to the light visualizing side with the reflecting layers 10c, 20c of the pad electrode. Namely, absorption of light by the semiconductor light emitting element can be reduced to improve light extracting efficiency of the light emitting device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor light emitting element and a light emitting device including the same, and more particularly to a semiconductor light emitting element related to an electrode with improved light reflectivity and a light emitting device including the same.

  Nitride-based compound semiconductor light-emitting elements emit light of a bright color that is small and power efficient. In addition, a light emitting element which is a semiconductor element does not have a concern about a broken ball. Further, it has excellent initial driving characteristics and is strong against vibration and repeated on / off lighting. Because of such excellent characteristics, semiconductor light emitting devices such as light emitting diodes (LEDs) and laser diodes (LDs) are used as various light sources. In particular, in recent years, as a light source for illumination replacing a fluorescent lamp, attention has been attracted as next-generation illumination with lower power consumption and longer life, and further improvement in light emission output and improvement in light emission efficiency are required.

  An example of a typical semiconductor light emitting device is shown in FIG. FIG. 27A is a plan view of the semiconductor light emitting device 100, and FIG. 27B is a cross-sectional view taken along line B-B ′ in the semiconductor light emitting device 100 of FIG. In the GaN-based compound semiconductor device 100 shown in this figure, the semiconductor layer 105 involved in light emission includes an n-type nitride semiconductor layer 102 grown on the sapphire substrate 101, a light-emitting layer 103, and a p-type nitride semiconductor layer 104. It is configured. Electrodes for flowing electricity to the semiconductor layer 105 are a positive electrode made up of a transparent electrode 106 formed on the p-type nitride semiconductor layer 104 and a p-type pad electrode 107, and an n-type nitride semiconductor layer 102. And a negative electrode on which an n-type pad electrode 108 is disposed. The n-type pad electrode 108 is formed on the exposed n-type semiconductor layer 102 by cutting away a part of the light-emitting layer 103 in order to connect to the lower side of the pn junction. Further, a protective film 109 for protecting the element is coated on the outermost surface. The pad electrodes 107 and 108 are connected to members (not shown) for electrically connecting the semiconductor layer 105 and external electrodes such as wire bonding wires and flip chip bumps. In general, since a wire made of Au is used, Au is adopted on the outermost surfaces of the pad electrodes 107 and 108 connected thereto in consideration of the bonding property with the wire.

  In the semiconductor light emitting device 100 as described above, when face-up mounting is performed with the electrode formation surface as the main light extraction surface, the light emitted from the light emitting layer 103 is emitted from the formation surface side of the pad electrode 107 which is the light viewing side. Not only that, part of the light also emits light in the horizontal plane direction.

Semiconductor light-emitting elements with improved light extraction efficiency have been developed by guiding light traveling in the horizontal plane direction to the viewing side (for example, Patent Document 1 and Patent Document 2). In the semiconductor light emitting device 200 in FIG. 28, the same members as those in FIG. 27 are denoted by the same reference numerals, and detailed description thereof is omitted. The n-type pad electrode 108 of the semiconductor light emitting device 200 has a two-layer structure in which gold (Au) is laminated on the upper surface of panadium (Pd), tantalum (Ta), and platinum (Pt), and the upper surface of the n-type pad electrode 108. Are formed at substantially the same position as the upper surface of the p-type pad electrode 107. The n-type pad electrode 108 has a side surface having an inclination angle of about 45 °, and the upper surface is tapered. In addition, a reflective film 201 made of Ag is formed on the surface of the n-type pad electrode 108. With this structure, it is possible to improve light extraction efficiency by reflecting light emitted from the light emitting layer 103 toward the viewing side and guiding the light.
JP 2004-128321 A JP 2005-19530 A

  With the semiconductor light emitting device described above, the light guide path of the light emitted from the light emitting layer can be corrected with a reflective film. However, even if the light traveling direction can be changed to the light viewing side, a part of the light is emitted. May be irregularly reflected by repeating the reflection one or more times by members constituting the light emitting device, changing the path to the light emitting element side again, that is, there is a possibility of returning light. The return light causes deterioration of characteristics of the light emitting element and reduction of light extraction efficiency. In particular, when the return light travels to the pad electrodes 107 and 108, the loss of light is large. This is because, conventionally, the surface of the pad electrodes 107 and 108 is generally made of Au in consideration of the bonding property with the wire, but Au has a characteristic of absorbing light. Thereby, the light output of the whole light-emitting device will reduce.

  For the same reason, when a part of the light emitted from the light emitting layer travels to the lower layer side of the pad electrodes 107 and 108, it is absorbed by Au constituting the pad electrode and light is emitted outside the light emitting element. There was a problem that was not. As shown in FIG. 27B, at the interface between the transparent electrode 106 and the p-type nitride semiconductor layer 104 such as GaN, the difference in refractive index between the two is small, so that the total reflection angle becomes narrow and most of the light. Will be transmitted. Therefore, part of the light from the light emitting layer 103 is absorbed by the lower surface of the p-type pad electrode 107 that contacts the light emitting layer 103, and the light itself may not be emitted outside the light emitting element. As a result, the light extraction efficiency decreases.

  The present invention has been made to solve the conventional problems. An object of the present invention is to provide a light emitting device that reduces the loss of light absorbed by an electrode and improves the light output.

  In order to achieve the above object, a first light emitting device of the present invention is a light emitting device including a semiconductor light emitting element 1 and a light scattering member 33 capable of reflecting or scattering light emitted from the semiconductor light emitting element 1. The semiconductor light emitting element 1 includes a first conductive type semiconductor layer 3, a light emitting layer 4 formed on at least a part of the first conductive type semiconductor layer 3, and a second conductive type formed on the light emitting layer 4. And a second conductivity type electrode 10 provided on at least a part of the second conductivity type semiconductor layer 5 and supplying a current to the second conductivity type semiconductor layer 5 are sequentially stacked. A first conductivity type electrode which is at least part of the first conductivity type semiconductor layer 3 and is disposed on the same plane side as the second conductivity type electrode 10 and supplies a current to the first conductivity type semiconductor layer 3 20 and the stacking direction of the semiconductor light emitting device 1, the first conductive type electrode and the second conductive type At least one of the mold electrodes 20 and 10 is formed of at least two layers including a reflective layer 20c and 10c on the surface side and a first layer located on the lower layer side of the reflective layers 20c and 10c. The reflectivity of the layers 20c and 10c is higher than the reflectivity of the first layer, the reflection side of the reflection layers 20c and 10c and the light emission side of the semiconductor light emitting element 3 are on the same plane side, and contains a light scattering member It is characterized in that it is sealed with a sealing member 36.

  Further, the second light emitting device of the present invention is characterized in that the sealing member 36 has a distribution region of the light scattering member 33 on the semiconductor light emitting element 1 side.

  Further, the third light emitting device of the present invention is characterized in that the reflectance of the reflective layers 20c and 10c is 90% or more.

  In the fourth light emitting device of the present invention, the first conductivity type electrode and the second conductivity type electrode have external connection portions 14b and 14a connected by a conductive member 35 that can be electrically connected to the external electrode. The reflectance of the reflection layers 20c and 10c is higher than that of the external connection portions 14b and 14a.

  The fifth light emitting device of the present invention is characterized in that the external connection portions 14b and 14a are formed with through holes in the reflective layers 20c and 10c, and the first layer is exposed through the through holes.

  In the sixth light emitting device of the present invention, the first conductivity type electrode 20 and the second conductivity type electrode 10 have a lowermost layer on the lower layer side of the first layer, and the lowermost layer is the reflective layers 20b, 10b. The reflectance of the lowermost reflective layers 20b and 10b is higher than the reflectance of the reflective layers 20c and 10c on the surface.

  In the seventh light emitting device of the present invention, the first conductivity type electrode and the second conductivity type electrodes 20 and 10 are formed of at least two layers in the stacking direction of the semiconductor light emitting element 1, and the first conductivity type electrode One of the electrodes 20 and the second conductivity type electrode 10 has a reflective layer on the surface side, and the other electrode has a reflective layer in the lowermost layer, and the reflectance of the lowermost reflective layer is The reflectance of the reflective layer is higher than that of the reflective layer, and the reflective side of the reflective layers 20c and 10c and the light emitting side of the semiconductor light emitting element 3 are on the same plane side and are sealed with a sealing member 36 containing a light scattering member. It is characterized by that.

  The eighth light-emitting device of the present invention is characterized by comprising a plurality of semiconductor light-emitting elements 1.

  In the ninth light-emitting device of the present invention, the reflective layers 20c and 10c have a metal layer composed of at least one of Ag, Al, and Rh, or a single layer or multiple layers of an alloy including the metal layer. And

  The tenth light emitting device of the present invention is characterized in that the scattering member 33 is a YAG phosphor or a LAG phosphor.

  According to the first and fourth to fifth aspects of the present invention, the return light to the semiconductor light emitting element side generated when a part of the light emitted from the semiconductor light emitting element is reflected or scattered by the light scattering member is reflected on the surface of the electrode. Since it can be reflected by the layer, absorption into the semiconductor light emitting element can be suppressed. Therefore, the life characteristics of the semiconductor light emitting device can be improved. Further, the light traveling direction can be guided to the light observation surface side, which is the substantially laminating direction of the semiconductor light emitting elements, by the reflection layer, thereby improving the light extraction efficiency.

  Further, according to the second and third inventions, the return light to the element side can be guided to the light side surface side with high efficiency, so that the light loss can be suppressed and the output of the light emitting device can be further improved.

  According to the sixth invention, since a part of the light emitted from the light emitting layer is reflected by the reflective layer provided on the lower layer side of the electrode, the light absorption to the electrode can be suppressed and the light extraction efficiency from the element itself can be improved. Can be improved.

  According to the seventh aspect, the reflective layer can be provided at the electrode position corresponding to the amount of received light.

  According to the eighth aspect of the invention, the traveling direction of the primary light that is the emitted light from the light emitting element can be guided to the light observation surface side by the reflection layer of the adjacent light emitting element. Moreover, since the area of the reflective layer increases as a whole, the amount of light guided to the light viewing side in the secondary light reflected by the light scattering member increases.

  According to the ninth aspect, a reflective layer having a high reflectance can be obtained.

  According to the tenth aspect of the invention, in addition to the effect of reflecting or scattering light, the wavelength of light emitted from the light source can be converted, so that a light emitting device having high luminous efficiency in a predetermined color gamut can be obtained. In addition, if a light source having a predetermined peak wavelength is selectively mounted, a light emitting device that can emit a desired emission color with high efficiency is obtained, and the wavelength width of the output light that can be realized increases.

  Embodiments of the present invention will be described below with reference to the drawings. However, the following examples illustrate a semiconductor light emitting element and a light emitting device including the semiconductor light emitting element for embodying the technical idea of the present invention. The present invention includes the semiconductor light emitting element and the same. The following light emitting devices are not specified. Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the embodiments are indicated in the “claims” and “means for solving problems” sections. It is appended to the members shown. However, the members shown in the claims are not limited to the members in the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the examples are not intended to limit the scope of the present invention only unless otherwise specified, but are merely illustrative examples. Only. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

(Embodiment 1)
(Semiconductor light emitting device)
A semiconductor light emitting device 1 according to the first embodiment will be described with reference to FIG. FIG. 1A is a plan view and FIG. 1B is a cross-sectional view. As shown in FIG. 1B, a semiconductor light emitting element 1 such as an LED is formed on a sapphire substrate 2a which is a growth substrate 2 (on the upper side in FIG. 1B) with a first conductive type semiconductor layer 3. A semiconductor layer 8 in which an n-type semiconductor layer 3a, a light emitting layer 4, and a p-type semiconductor layer 5a, which is the second conductive semiconductor layer 5, are epitaxially grown in this order, and a light-transmissive conductive layer formed on the semiconductor layer 8 6. As the crystal growth method, for example, metal-organic chemical vapor deposition (MOCVD), hydride vapor deposition (HVPE), hydride CVD, MBE (molecular beam epitaxy) and the like can be used.

  Subsequently, the light emitting layer 4 and a part of the p-type semiconductor layer 5a are selectively removed by etching to expose a part of the n-type semiconductor layer 3a. In this exposed region, the n of the first conductivity type electrode 20 is formed. A mold pad electrode 20a is formed. A p-type pad electrode 10 a that is the second conductivity type electrode 10 is formed on the same surface side as the n-type electrode and on the translucent conductive layer 6. Further, only the surfaces of the n-type pad electrode 20 a and the p-type pad electrode 10 a are exposed, and the other portions are covered with the protective film 7.

  In the present specification, the term “upper” as used on a layer or the like is not necessarily limited to the case where the upper surface is formed in contact with the upper surface, but includes the case where the upper surface is formed apart from the upper surface. It is used in the meaning including the case where an intervening layer is present. Hereinafter, each component of the semiconductor light emitting device 1 will be specifically described.

(Growth substrate)
The growth substrate 2 is a translucent substrate on which the semiconductor layer 8 can be epitaxially grown, and the size and thickness of the substrate are not particularly limited. As this substrate, an insulating substrate such as sapphire or spinel (MgA1 ₂ O ₄ ) whose main surface is any of the C-plane, R-plane, and A-plane, silicon carbide (6H, 4H, 3C), silicon , ZnS, ZnO, Si, GaAs, diamond, and oxide substrates such as lithium niobate and neodymium gallate that are lattice-bonded to a nitride semiconductor. In addition, a nitride semiconductor substrate such as GaN or AlN can be used as long as it is thick enough to allow device processing (several tens of μm or more). The heterogeneous substrate may be off-angle, and when using the sapphire C-plane, the range is 0.01 ° to 3.0 °, preferably 0.05 ° to 0.5 °. Further, a structure in which the growth substrate is removed after forming the semiconductor layer, a structure in which the taken-out semiconductor layer is bonded to a supporting substrate, for example, a conductive substrate, or the like can also be employed.

(Semiconductor layer)
As the semiconductor, the general formula _{In x Al y Ga 1-x} -y N (0 ≦ x, 0 ≦ y, x + y ≦ 1) A, B and P, may be mixed with As. Further, the n-type semiconductor layer 3a and the p-type semiconductor layer 5a are not particularly limited to a single layer or a multilayer. Further, the semiconductor layer 8 appropriately contains n-type impurities and p-type impurities. As the n-type impurity, a group IV or group VI element such as Si, Ge, Sn, S, O, Ti, or Zr can be used, preferably Si, Ge, or Sn, and most preferably Si. The p-type impurity is not particularly limited, and examples thereof include Be, Zn, Mn, Cr, Mg, and Ca, and Mg is preferably used. Thereby, each conductivity type semiconductor can be formed. The semiconductor layer 8 has a light emitting layer 4 which is an active layer, and this active layer has a single (SQW) or multiple quantum well structure (MQW). Details of the semiconductor layer 8 will be described below.

The semiconductor grown on the growth substrate 2 may be grown via an underlayer such as a buffer layer (not shown in FIG. 1). As the buffer layer, a nitride semiconductor represented by the general formula Al _a Ga _1-a N (0 ≦ a ≦ 0.8), more preferably Al _a Ga _1-a N (0 ≦ a ≦ 0.5). The nitride semiconductor shown in FIG. The thickness of the buffer layer is preferably 0.002 to 0.5 μm, more preferably 0.005 to 0.2 μm.

Next, the n-type semiconductor layer 3a is grown. First, an n-type contact layer (not shown) is grown. The n-type contact layer generally has a composition that is larger than the band gap energy of the active layer, and Al _j Ga _1-j N (0 ≦ j <0.3) is preferable. The thickness of the n-type contact layer is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more. Further, a clad layer or the like may be interposed between the n-type contact layer and the active layer.

The active layer functions as the light emitting layer 4, and includes a well layer made of at least Al _a In _b Ga _1-ab N (0 ≦ a ≦ 1, 0 ≦ b ≦ 1, a + b ≦ 1), and Al _c In _d Ga. _{And a} barrier layer made of 1-cdN (0 ≦ c ≦ 1, 0 ≦ d ≦ 1, c + d ≦ 1). The semiconductor used for the active layer may be any of non-doped, n-type impurity doped, and p-type impurity doped. Preferably, by using a non-doped or n-type impurity doped nitride semiconductor, the output of the light-emitting element can be increased. More preferably, when the well layer is undoped and the barrier layer is n-type impurity doped, the output and the light emission efficiency of the light emitting element can be increased. Further, by including Al in the well layer used in the light emitting element, a wavelength near 365 nm which is the band gap energy of GaN or shorter than that can be obtained. The wavelength of light emitted from the active layer is approximately 360 to 650 nm, preferably 380 to 560 nm, depending on the purpose and application of the light-emitting element.

  The thickness of the well layer is preferably 1 nm or more and 30 nm or less, more preferably 2 nm or more and 20 nm or less, and further preferably 2 nm or more and 20 nm or less, and a plurality of well layers are provided via a single quantum well, a barrier layer, or the like. It can be a multiple quantum well structure of a well layer.

The barrier layer is preferably doped or undoped with a p-type impurity or an n-type impurity, more preferably doped or undoped with an n-type impurity, as in the case of the well layer. It is. For example, the LED, preferably 5 × ¹⁰ 16 / cm ³ or more 2 × ¹⁰ 18 / cm ³ or less. In this case, the well layer preferably does not substantially contain n-type impurities or is grown undoped. In addition, when the n-type impurity is doped in the barrier layer, all the barrier layers in the active layer may be doped, or a part may be doped and a part may be undoped. Moreover, it is preferable to dope the barrier layer disposed on the n-type layer side in the active layer.

Next, for example, the following layers are formed as the p-type semiconductor layer 5a on the active layer. First, the p-type cladding layer is not particularly limited as long as it has a composition larger than the band gap energy of the active layer and can confine carriers in the active layer. For example, Al _k Ga _1-k N (0 ≦ k <1) is used, and Al _k Ga _1-k N (0 <k <0.4) is particularly preferable. The film thickness of the p-type cladding layer is not particularly limited, but is preferably 0.01 to 0.3 μm, more preferably 0.04 to 0.2 μm. The p-type impurity concentration of the p-type cladding layer is 1 × 10 ¹⁸ to 1 × 10 ²¹ / cm ³ , preferably 1 × 10 ^{19 to} 5 × 10 ²⁰ cm ³ . The p-type cladding layer may be a single layer or a multilayer layer (superlattice structure). In the case of a multilayer film layer, for example, as a layer having a small band gap energy, as in the case of the n-type cladding layer, In ₁ Ga _1-l N (0 ≦ l <1), Al _m Ga _1-m N (0 ≦ m <1, m> l). In the case of a superlattice structure, the thickness of each layer forming the multilayer layer is preferably 100 mm or less, more preferably 70 mm or less, and further preferably 10 to 40 mm. In the case of a multilayer film layer, p-type impurities may be doped into at least one of a layer having a large band gap energy and a layer having a small band gap energy.

For the p-type contact layer, Al _f Ga _1-f N (0 ≦ f <1) is used, and in particular, an ohmic electrode can be formed by being composed of Al _f Ga _1-f N (0 ≦ f <0.3). It is possible to make a good ohmic contact with the p electrode. The p-type impurity concentration is preferably 1 × 10 ¹⁷ / cm ³ or more.

  After the nitride semiconductor is grown on the growth substrate 2 as described above, the wafer is taken out of the reaction apparatus, and then heat-treated at 450 ° C. or higher in an atmosphere containing oxygen and / or nitrogen. As a result, hydrogen bonded to the p-type layer is removed, and a p-type semiconductor layer 5a exhibiting p-type conductivity is formed.

  Further, examples of the laminated structure of the semiconductor layer 8 include a homo structure having a MIS junction, a PIN junction, and a PN junction, a hetero structure, and a double hetero structure. Each layer may have a superlattice structure, or may have a single quantum well structure or a multiple quantum well structure in which the light emitting layer 4 as an active layer is formed in a thin film in which a quantum effect is generated. Next, a mask (not shown) having a predetermined shape is formed on the surface of the p-type semiconductor layer 5a, and the p-type semiconductor layer 5a and the light emitting layer 4 which is an active layer are etched to form n at a predetermined position. The n-type contact layer constituting the type semiconductor layer 3a is exposed.

(Translucent conductive layer)
Further, the translucent conductive layer 6 is formed on the p-type semiconductor layer 5a. By forming the conductive layer almost on the front surface of the exposed p-type semiconductor layer 5a, the current can be spread uniformly over the entire p-type semiconductor layer 5a. In addition, by providing translucency, the electrode side can be a light emission observation surface. Note that translucency means that the light emission wavelength of the light emitting element can be transmitted, and does not necessarily mean colorless and transparent. The translucent conductive layer 6 preferably contains oxygen in order to obtain ohmic contact. There are various types of translucent conductive layers 6 containing oxygen, and preferably an oxide containing at least one element selected from the group consisting of zinc (Zn), indium (In), and tin (Sn) To do. Specifically, it is desirable to form a light-transmitting conductive layer 6 containing an oxide of Zn, In, Sn, such as ITO, ZnO, In ₂ O ₃ , SnO ₂ , and preferably ITO is used. Alternatively, a metal film formed by sputtering a metal such as Ni with a film thickness of 30 mm or the like to make it transparent may be used. As described above, the conductive layer is formed on almost the entire surface of the exposed p-type semiconductor layer 5a, so that the current can be uniformly spread over the entire p-type semiconductor layer 5a. Moreover, by providing translucency, the electrode side can be used as a light emission observation surface. In the following example, an example in which an ITO translucent electrode is used as the translucent conductive layer 6 will be described.

  In order to contain oxygen atoms in the light-transmitting conductive layer 6, after forming a layer containing oxygen atoms, heat treatment may be performed in an atmosphere containing oxygen. Alternatively, oxygen atoms can be contained in each layer by reactive sputtering, ion beam assisted vapor deposition, or the like, but heat treatment is most excellent from the standpoint of process ease. Moreover, the thickness of the translucent conductive layer 6 is set to such a thickness that an uneven surface can be formed, and is preferably 1 μm or less, more preferably 100 to 5000 mm.

(Pad electrode)
The first and second conductivity type electrodes in the first embodiment will be described with reference to FIG. The semiconductor light emitting device 1 of FIG. 2 is the same as the semiconductor light emitting device 1 shown in FIG. 1, and therefore, the same members are denoted by the same reference numerals and detailed description thereof is omitted. The pad electrodes 10a and 20a which are metal electrode layers as the second conductivity type electrode 10 and the first conductivity type electrode 20 in FIG. 2 are the translucent conductive layer 6 provided on the p-type semiconductor layer 5a side, and exposed. The n-type contact layer is formed on the n-type contact layer constituting the n-type semiconductor layer 3a. Further, the pad electrodes 10a and 20a contain a single layer or multiple layers of metal layers. Further, the surface of the protective film and the surface layer of the pad electrodes 10a and 20a are etched to form holes, and the lower layer side of the electrodes is formed. A conductive member 35 such as a bonding wire is connected to the external connection portions 14a and 14b which are exposed regions. For example, if an Au layer located below the surface layers 10c and 20c of the pad electrodes 10a and 20a is exposed and an Au photoconductive member is bonded thereto, bonding with the same material can be achieved. It is possible to further improve the bonding property. Thereby, the reliability of the apparatus can be increased. Furthermore, the conductive member 35 is connected to an external electrode (not shown), and thereby it is possible to supply power to the semiconductor light emitting element 1 via the conductive member 35. Alternatively, a conductive member such as an Au bump may be disposed on the surface of the pad electrodes 10a and 20a, and an electrical connection between the electrode of the light emitting element and the external electrode facing each other through the conductive member may be achieved. Further, the p-type pad electrode 20a is partly in direct contact with the translucent conductive layer 6, so that a current can flow uniformly through the translucent conductive film.
Thus, by providing a through hole or an opening in the electrode, a suitable external connection is made at that portion, and the remaining surface layer provides a structure that realizes light reflection. For this reason, preferably, the light reflectance of the reflective layer of the outermost surface layer is made higher than the surface of the lower layer side exposed at the through-hole and opening of the electrode.

In the semiconductor light emitting device 1 shown in the examples of FIGS. 1B and 2, the p-type pad electrode 10 a is provided with a reflective layer 10 c having a high reflectivity on the outermost surface layer constituting the outer surface side of the semiconductor light emitting device 1. . High reflectivity refers to a state in which 90% or more of light can be reflected. Specifically, a single layer or alloy containing at least one of Ag, Al, and Rh is used as a member of the reflective layer. Regarding the reflectance, Ag is 90% or more, and Al is about 90%. Both members have high reflectance and excellent life characteristics. Thereby, absorption of a light emitting element made of a nitride semiconductor at a wavelength of about 360 nm to about 650 nm, preferably about 380 nm to 560 nm can be suppressed. Rh is excellent in light reflectivity and barrier properties, and can be suitably used because light extraction efficiency is improved. In the first embodiment, Al is used as the reflective layer of the surface layer in consideration of stability in addition to the above features. Also in the n-type pad electrode 20a, a reflective layer 20c similar to the p-type pad electrode 10a can be provided on the outermost surface layer on the outer surface side. In the semiconductor light emitting devices 1, 1 c, 1 d, 1 e, and 1 f in FIGS. 1, 3, 4, 5, and 6, the reflective layers 10 c and 20 c are provided on the outermost surface layers of the electrodes 10 and 20. The reflective layer may be provided on at least one of the p-type pad electrode 10a and the n-type pad electrode 20a, and is preferably provided on both. Thereby, the light extraction efficiency of the light emitting device described later can be increased. Further, on these reflective layers, a substantially transparent electrode protective layer (not shown) made of the same material as the protective film such as SiO ₂ and Al ₂ O ₃ can be covered in the same pattern as the electrodes. Thereby, metal oxidation of the reflective layer is suppressed.

  In addition to the outermost surface layer 10c of the p-type pad electrode, the reflective layer 10b can also be provided on the lowermost layer that is in contact with the translucent conductive layer 6. Similarly, in the n-type pad electrode 20a, in addition to the outermost surface layer 20c, a reflective layer can be formed on the lowermost layer 20b that is in contact with the n-type semiconductor layer 3a. That is, in the p-type and n-type pad electrodes 10a and 20a, a reflective layer can be formed in the lowermost layer in addition to the outermost surface layer. Thereby, although mentioned later in detail, the optical loss inside the semiconductor light emitting element 1 can be reduced, and by extension, the light extraction efficiency of the light emitting device can be increased.

In addition, regarding the formation position of the reflective layer, a reflective layer may be provided on the outermost surface layer of one of the pad electrodes 10a and 20a, and a reflective layer may be provided on the lowermost layer of the other electrode. For example, by providing the reflective layer 10b on the lowermost layer side of the p-type pad electrode 10a, light loss inside the device can be reduced. Further, by forming the reflective layer 20c only on the surface layer without providing the reflective layer in the lowermost layer of the n-type pad electrode 20a, the reflective layer can be configured only in the region where the amount of received light is large in the n-type pad electrode 10a. . That is, the member can be used with high efficiency by selectively forming the reflective layer.
Further, as the above Ag, an Ag alloy such as APC (Ag added with Pd, Cu) can also be used. Ag, a white metal element such as Pd, Cu, Mg, etc., for example, Pt, Co, Au, Pd Ti, Mn, V, Cr, Zr, Rh, Cu, Al, Mg, Bi, Sn, Ir, Ga, Nd, and one or more alloys selected from the group consisting of Re and 0. 0.1 to 10 atm%, preferably about 5 wt% or less. As Al alloy, you may use what added about 0.1-5 atm% of Si, Cu, Ta, Zr etc. to Al.

(Electrode shape)
In addition, the semiconductor light emitting element 1 in the example of FIG. 1A has a substantially square shape in a plan view. Within this substantially square shape, a pair of p-type pad electrode 10a and n-type pad electrode 20a is formed in each of the two rectangular regions divided by the center line connecting the midpoints of the opposite sides. Provided. A p-type pad electrode 10a is provided at one corner of the semiconductor light emitting element 1 having a substantially square shape, which is composed of a long side and a short side in a rectangular region divided into two. An n-type pad electrode 20a is formed in the vicinity of the central region of the other short side facing the short side in contact with the p-type pad electrode 10a. Similar members are provided symmetrically in the other rectangular region with respect to the substantially square center line.

  Further, the p-type pad electrode 10a has an elongated conductive portion 9 that is elongated. The stretched conductive portion 9 in the example of FIG. 1A is stretched from the circular p-type pad electrode 10a to the peripheral edge of the substantially square semiconductor light emitting element 1 and further to the central region that divides the two sets of pn electrodes. These extended conductive parts 9 are connected. The extending direction and the number of the extending conductive portions 9 are not particularly limited and can be changed as appropriate, whereby the wiring electrode area and the current supply amount to the element can be freely changed. For example, the stretched conductive portion 9 can be eliminated, and the n-type electrode or both electrodes can be provided depending on the structure and area of the light emitting element. As an example, various electrode structures are shown in FIG. 3, FIG. 4, FIG. 5, and FIG. 3, 4, 5, and 6, the same or similar members as those of the semiconductor light emitting device 1 shown in FIG. Detailed description is omitted. Each of the semiconductor light emitting devices 1c, 1d, 1e, and 1f has an n-type extended conductive portion 9b that is extended by one or more than the n-type pad electrode 20a, and the plurality of n-type extended conductive portions 9b are substantially comb-like parallel. Located in. In addition to the stretched region in the stretched conductive part 9b of the semiconductor light emitting device 1 shown in FIG. 1 (a), the stretched conductive part 9 stretched from the p-type pad electrode is between the n-type stretched conductive parts 9b located in parallel. Can be stretched, and the tip thereof is formed in the vicinity of the n-type pad electrode 20a. The extended conductive portions 9 and 9b may be formed with a structure, material, and process different from those of the metal layers on the pad electrodes 10a and 20a and the translucent conductive layer 6, but are preferably formed integrally with the pad electrode. . Thereby, a reflective layer can be provided also in the outermost surface and lowermost layer of the extending | stretching electroconductive parts 9 and 9b, and the comprehensive area of a reflective layer increases. The shape of the semiconductor light emitting element 1 and the shape of the region where the pair of pad electrodes are formed can be changed as appropriate. For example, in a region where a pair of pad electrodes are formed, each pad electrode is formed separately at both ends in the longitudinal direction, and the width direction of the element is thinned when the direction substantially perpendicular to the longitudinal direction is the width direction. Thus, extraction of light from the width direction can be improved while minimizing light absorption caused by reflection of light.

  In another embodiment according to the present invention, part of the pad electrodes 10 a and 20 a as the second conductive type electrode 10 and the first conductive type electrode 20 is in a through hole provided in the translucent conductive layer 6. It may be extended and provided directly on the semiconductor layer 8 or may be provided directly on the semiconductor layer 8 at the outer edge of the translucent conductive layer 6. As described above, part of the pad electrodes 10a and 20a is directly provided on the nitride semiconductor layer 8 to prevent the pad electrodes from being peeled off. In addition, the interface between the reflective layers 10b and 20b at the lowermost layer of the pad electrode and the translucent conductive layer 6 can be an uneven surface. Thereby, a lot of light can be extracted to the outside, and the output is further improved.

The pad electrodes 10a and 20a and the stretched conductive portions 9 and 9b formed on the p-type nitride semiconductor layer 5a side and the n-type nitride semiconductor layer 3a side have the same configuration and type of metal used. Is preferred. As a result, the pad electrodes 10a, 20a and the extended conductive portions 9, 9b can be formed simultaneously on the p-type nitride semiconductor layer 5a side and the n-type nitride semiconductor layer 3a side, that is, the formation process can be made one. Therefore, the process of forming pad electrodes 10a and 20a can be simplified as compared with the case where p-type nitride semiconductor layer 5a side and n-type nitride semiconductor layer 3a side are separately formed. Furthermore, in the case of the pad electrodes 10a and 20a according to the present embodiment, the type of metal constituting the pad electrodes 10a and 20a and the stacking order may be changed, and there is no change in design such as the electrode formation area. Conventional mask patterns can be used. That is, since a dedicated design is not required, the cost can be reduced in addition to the simplification of the process. As the pad electrodes 10a and 20a having the reflective layer on the outermost surface layer of the electrode, for example, Ti / Rh / Au / Rh, Ti / Rh / Au / Rh / Al, or Ti / Rh / Au / Rh / Al ₂ O ₃ or Ti / Rh / Al / SiO ₂ can be used. Here, Al ₂ O ₃ and SiO ₂ are electrode protective layers of the electrodes. Further, Ti located in the lowermost layer functions as an adhesion layer with the translucent conductive layer 6 in contact with the p-type pad electrode 10a, and makes contact with the n-type contact layer in the n-type pad electrode 20a. It functions as an ohmic electrode. If common Ti is used for the lowermost layer of both pad electrodes 10a and 20a like said electrode layer, it can serve as the function of each lowermost layer. However, both the pad electrodes 10a and 20a can be manufactured in separate steps, whereby the two can have different structures. In this case, it is sufficient if the lowermost layer of each electrode is not formed of a common member and the above functions in the lowermost layer of each electrode are provided. Furthermore, the location where the reflective layer is formed by the electrodes can be different.

  The first electrode and the second electrode of the present invention have at least the outermost reflective layer and its lower layer, and the light reflectance is higher in the reflective layer than on the lower layer side. On the lower layer side, there are provided contact layers such as a layer for ohmic contact with the semiconductor layer and a layer for adhesion with the transmissive conductive layer, and further exposed between the barrier layer interposed therebetween, the above-described through hole, and opening. The external connection layer may be provided. Specifically, a structure of at least three layers of a contact layer / barrier layer (external connection layer) / reflection layer is preferable in order from the semiconductor layer side, and more preferably, the barrier layer and the external connection layer are formed as separate layers. When provided between the layer and the reflective layer, the function of each layer is preferably enhanced, which is preferable. Moreover, when providing a reflective layer in the lowest layer, it can be set as the material which bears it to the said contact layer. In addition, each of these layers may be composed of a plurality of layers, and the material of each layer is a metal, an alloy, or the like corresponding to various functions. Furthermore, the ohmic contact function with the semiconductor layer can be separated from the contact layer, and a translucent conductive layer can be provided under the contact layer of each electrode, as in the p-electrode in the present application. , A translucent conductive layer, and first and second electrodes in this order. The translucent conductive layer is provided in a larger area or wider in cross section than the light-shielding first and second electrodes having lower light transmittance than the p-electrode in the present application, A structure in which current is diffused and an element structure in which a region exposed from the first and second electrodes is used as a light extraction region are preferable, and it is particularly suitable for the second electrode on the light emitting layer.

Each electrode has at least a portion for external connection, preferably has an extended conductive portion, and more preferably has a structure in which the external connection portion is wider in cross section than the extended conductive portion. Preferably, at least a reflective layer is provided on the outermost surface layer of the stretched conductive portion, and a lowermost reflective layer is provided on the external connection portion.
In the case where a reflective layer having a high reflectance is provided on the lowermost layer and the outermost surface layer, it is preferable that each of them be a reflective layer having a higher reflectance than at least a layer interposed therebetween, more preferably the lowermost layer. The reflectance is made higher than that of the outermost surface layer. As a result, the light inside the semiconductor layer is larger than the return light from the outside of the semiconductor layer, and a structure corresponding to this can be obtained, and even Ag that is relatively unstable in a highly reflective material or an alloy thereof is used in the lowermost layer. That can be suppressed. In addition, in order to increase the adhesion to the lowermost reflective layer, a thin film that suppresses light reflectance reduction, and an adhesive layer may be provided between the lower reflective layer and the semiconductor layer or the light-transmitting conductive layer. it can.

  Here, the barrier layer only needs to prevent and protect diffusion of the lower layer (lowermost layer) / upper layer (surface layer), and specific materials include high melting point materials such as W and Mo, White metal elements, Ni, Au, etc., preferably Pt, W, Mo, Ni are preferably used. Examples of the external connection material include Au and Al. The thickness of each layer is not particularly limited, but it is preferably 0.05 to 5 μm, and the reflective layer is preferably formed as a thin film as compared to other layers (upper layers), barrier layers, external layers The connection layer is formed to be relatively thicker than the reflective layer, and the thin adhesion layer is formed with a thickness of about 1 to 50 nm. In addition, a protective layer may be provided between the layers. For example, Ti and Ni are interposed in the adhesion layer.

  Specific examples of such an electrode include Rh in addition to Ag (reflection) /Ni.Ti (adhesion) / Pt (barrier) / Au (external connection) / Al (reflection) on a Ni thin film layer of about 10 nm. (Reflection) / Pt (barrier) / Au (external connection) / Al (reflection), Al (reflection) / Pt (barrier) / Au (external connection) / Rh (reflection), Ti (adhesion layer) / Rh (reflection) ) / Pt (barrier) / Au (external connection) / Al (reflection), Al (reflection) / W (barrier) / Pt (barrier) / Au (external connection) / Al (reflection), Ni (adhesion layer) / A structure in which Ag (reflection) / Ni (adhesion / barrier) / Ti (adhesion layer) / Au (external connection) / Al (reflection) are laminated in this order on the surface of the semiconductor layer, or a light-transmitting conductive layer is formed below the structure. There are stacked structures.

(Effect of lower reflective layer)
FIG. 7 is a cross-sectional view of the semiconductor light emitting device 1 according to the first embodiment. With reference to FIG. 7, an example of the progress of light of the emitted light L from the light emitting layer 4 will be described. At least a part of the emitted light L travels in the stacking direction (substantially above in FIG. 7) and passes through the translucent conductive layer 6 as it is. This is because the total reflection angle is narrow at the interface between the p-type semiconductor layer 5a (for example, refractive index 2.46) and the translucent conductive layer 6 (for example, refractive index 2.00) because the difference in refractive index between the two is small. This is because most of the light travels. The transmitted light L is reflected by the p-type pad electrode 10a and the reflective layer 10b having a high reflectivity formed in the lowermost layer of the stretched conductive portion 9. That is, conventionally, the emitted light that has been absorbed by the metal constituting the p-type pad electrode 10a can be extracted outside the light emitting element without loss of light. Furthermore, by forming the reflective layer 10b, deterioration at the interface between the p-type pad electrode 10a, which is a metal electrode, and the translucent conductive layer 6 can be reduced, and peeling, deterioration of electrical characteristics, and the like can be suppressed.

  On the other hand, the reflective layer 20b provided in the lowermost layer of the n-type pad electrode 20a is located below the light emitting layer 4 (lower side in FIG. 7). Therefore, the effect of guiding the emitted light L from the light emitting layer 4 to the outside of the element is small. Therefore, the reflective layer 20b is not necessarily provided in the lowermost layer of the n-type pad electrode. However, since the reflection layer 20b is provided in the lowermost layer of the n-type pad electrode, the p-type and n-type pad electrodes 10a and 20a can be formed of the same kind of material almost simultaneously as described above. This has the effect of simplifying the manufacturing process.

(Protective film)
After the pad electrodes 10a and 20a are formed, an insulating protective film 7 is formed on almost the entire surface of the semiconductor light emitting device 1 except for the region where wire bonding is performed. The protective film 7 is _{SiO 2, TiO 2, Al 2} O 3, available polyimide and the like.

  In addition, the size and shape of the semiconductor light emitting element and the number of mounted light emitting devices are not particularly limited, and may be determined in consideration of the element mounting area in the light emitting device, the desired light flux from the light emitting device, the light output amount, and the like. That's fine.

(Light emitting device)
Next, FIG. 8 shows a schematic cross-sectional view of a bullet-type light emitting device as the light emitting device according to Embodiment 1 of the present invention. The light emitting device 30 is in a concave cup 31 formed by a lead frame 34 made of a conductive member, and includes a light emitting element 32 mounted on the lead frame 34 and a light emitting layer of the light emitting element 32. 4 has a light scattering member 33 capable of reflecting or scattering at least a part of the light emitted from 4. Examples of the light scattering member 33 include diffusing agents such as barium titanate, titanium oxide, aluminum oxide, silicon oxide, silicon dioxide, heavy calcium carbonate, and light calcium carbonate, and mixtures containing at least one of these. be able to. As the phosphor, the light emitting element 32 is an LED which is the semiconductor light emitting element 1 described above. Positive and negative electrodes 39, which are first and second conductivity type electrodes formed on the light emitting element 32, are electrically connected to the lead frame 34 via a conductive member 35 such as a conductive bonding wire. Further, the light emitting element 32, the lead frame 34, and the bonding wire 35 are covered with a bullet-shaped mold 37 so that the lead frame electrode 34 a that is a part of the lead frame 34 protrudes. The mold 37 is filled with a light transmissive resin as the sealing member 36, and the resin contains a light scattering member 33. Further, the electrode 39 of the light emitting element 32 is contained in the layer of the light emitting element 32 by being electrically connected to the external electrode through the lead frame electrode 34a protruding from the resin 36, the conductive member 35, and the like. Light is emitted from the light emitting layer 4. The emission peak wavelength of the emitted light output from the light emitting layer 4 is not particularly limited, but in the first embodiment, the short wavelength region from near ultraviolet to visible light is around 240 nm to 500 nm, preferably 380 nm to 420 nm or 450 nm to A semiconductor light emitting device having an emission spectrum at 470 nm was used. In addition, the light scattering member 33 in the resin according to the first embodiment is unevenly distributed in the vicinity of the semiconductor light emitting element 1 as illustrated. As a result, the effect of reflecting or scattering the light emitted from the semiconductor light emitting element 1 is enhanced, and the light emitted from the light emitting device 30 can have a wide range of light emission angles, so that light diffused in all directions can be obtained.

  The material of the sealing member 36 is not particularly limited as long as it is translucent, and it is preferable to use a silicone resin composition, a modified silicone resin composition, etc., but an epoxy resin composition, a modified epoxy resin composition, an acrylic resin An insulating resin composition having translucency such as a composition can be used. Moreover, the sealing member 36 excellent in weather resistance, such as a silicone resin, an epoxy resin, a urea resin, a fluororesin, and a hybrid resin containing at least one of these resins, can also be used. Furthermore, the sealing member 36 is not limited to an organic material, and an inorganic material having excellent light resistance such as glass and silica gel can also be used. Furthermore, by making the light emitting surface side of the sealing member 36 have a desired shape, a lens effect can be provided, and light emitted from the light emitting element chip can be focused. In Embodiment 1, a silicone resin is used as the sealing member.

  Moreover, it is preferable that the sealing member 36 has adhesiveness. By providing the sealing member 36 with adhesiveness, it is possible to improve the adhesion between the light emitting element 32 and the central region of the lead frame 34 on which the light emitting element 32 is placed. The adhesiveness includes not only the adhesive exhibiting adhesiveness at normal temperature, but also the adhesive that adheres to the sealing member 36 by applying predetermined heat and pressure. Further, in order to increase the fixing strength of the sealing member 36, it can be dried in addition to applying temperature and pressure.

(Wavelength conversion member)
By mixing a wavelength conversion member such as a fluorescent material that emits fluorescence when excited by the light of the light emitting element 32 into the sealing member 36, the light of the light emitting element 32 is converted into light of a different wavelength, and the light of the light emitting element 32. And the color-mixed light of the light converted in wavelength by the wavelength conversion member can be taken out to the outside. That is, a part of the light from the light source excites the phosphor, so that light having a wavelength different from that of the main light source can be obtained. As the wavelength conversion member, a phosphor can be preferably used. This is because the phosphor also has the functions of light scattering and light reflection, so that it can serve as the light scattering member 33 in addition to the wavelength conversion function and obtain the light diffusion effect described above. The phosphors can be mixed in the sealing member 36 at a substantially uniform ratio, or can be blended so as to be partially unevenly distributed. For example, by separating the light emitting element 32 from the light emitting element 32 by a predetermined distance, it is difficult for heat generated in the light emitting element 32 to be transmitted to the fluorescent substance, and deterioration of the fluorescent substance can be suppressed. Further, two or more kinds of phosphors may be present in the light emitting layer composed of one layer on the surface of the light emitting device, or one or more kinds of phosphors may be present in the light emitting layer composed of two layers. Thereby, a light emitting device having a desired wavelength can be realized.

Typical phosphors include cadmium zinc sulfide associated with copper and YAG phosphors and LAG phosphors associated with cerium. In particular, at the time of high luminance and long-term use _{(Re 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: Ce (0 ≦ x <1,0 ≦ y ≦ 1, where, Re Is at least one element selected from the group consisting of Y, Gd, La, and Lu. As the wavelength conversion member of the first embodiment, YAG or LAG phosphor was used. In the light emitting device 30, for example, white color is obtained by color mixing of light emitted from the light source having the above wavelength and light having a wavelength different from that of the emitted light because part of the emitted light is excited by the phosphor. Can do. Further, as the phosphor, phosphor glass or phosphor-containing resin obtained by mixing phosphor in glass or resin may be used. Further, those that are resistant to heat generated from the light source and those that are weather resistant not affected by the use environment are more desirable.

In the light emitting device 30 according to Embodiment 1 of the present invention, the phosphor may be a mixture of two or more types of phosphors. That, Al, Ga, Y, La , the content of Lu and Gd and Sm are two or more kinds of _{(Re 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: mixed Ce phosphor Thus, RGB wavelength components can be increased. Further, it is possible to increase the reddish component by using a nitride phosphor having yellow to red light emission, and to realize illumination with high average color rendering index Ra, light bulb color LED, and the like. Specifically, by adjusting the amount of phosphors having different chromaticity points on the CIE chromaticity diagram according to the light emission wavelength of the light emitting device, the phosphors are connected with each other on the chromaticity diagram. Any point can be made to emit light.

(Effect of the reflective layer on the surface layer)
FIG. 9 is a partially enlarged view of the light emitting device 30 according to the first embodiment in the vicinity of the light emitting element 32 (external connection portions and conductive members of the pad electrodes 10a and 20a are omitted). An example of the traveling direction of the emitted light L emitted from the light emitting layer 4 of the LED that is the light emitting element 32 will be described using this. The emitted light L is reflected by the light scattering member 33 disposed on the LED side and scattered in all directions, and a part of the scattered light travels to the LED side. Conventionally, when the return light travels to the pad electrodes 10a and 20a, the light is absorbed by the Au metal that forms the outermost surface of the pad electrode, resulting in light loss. If it is pad electrode 10a, 20a provided with the structure of Embodiment 1, since the reflective layer 10c, 20c of the outermost surface layer is provided with a reflective layer having a high reflectivity, the traveling direction of the return light is substantially the light viewing side ( It is possible to guide to the substantially upper side in FIG. That is, light loss can be suppressed and light extraction efficiency as a light emitting device can be increased. Further, the return light to the light emitting element 32 side is not limited to the scattered light generated by the light scattering member 33. The light reflected by all members in the light emitting device 30 such as a lead frame is also included.

  As shown in FIG. 8, in the light emitting device 30 according to the first embodiment, the phosphor is not mixed in the sealing member 36 at a substantially uniform ratio but is settled in the vicinity of the light emitting element 32. In this way, by causing the phosphor to be unevenly distributed in the vicinity of the light emitting element 32, the return light of the wavelength-converted light can be reliably guided to the light viewing side by the reflective layers 10c and 20c on the outermost surface layer of the pad electrode. In addition, when a phosphor is used as the light scattering member 33, a desired wavelength conversion amount is reduced in the emitted light as a light emitting device realized by mixing the emitted light of the light emitting element and the converted light of the phosphor. Since it is possible to proceed to the light viewing side without any problem, the color mixing ratio can be stabilized, thereby reducing light unevenness for each light emitting device. Of course, since light loss can be reduced, the overall light extraction efficiency of the light emitting device increases.

  Further, by adopting a structure in which the light scattering member 33 is settled in the vicinity of the light emitting element 32, the phosphor layer can be uniformly and thinly applied in the vicinity of the light source of the light emitting body. Therefore, the use efficiency of materials and processes is increased by forming the phosphor layer only in necessary portions. In addition, it is highly productive and can handle many types of phosphors in the same process. The phosphor layer is preferably thinly coated with particles uniformly. This is because if the phosphor layer is too thick, the phosphor crystals overlap and cause shadowing, which reduces efficiency.

(Additive components)
In addition to the wavelength conversion member, the sealing member 36 can be added with an appropriate member such as a viscosity extender, a pigment, a fluorescent substance, or the like depending on the intended use, and thus a light emitting device having good directivity can be obtained. can get. Similarly, various colorants can be added as a filter material having a filter effect of cutting unnecessary wavelengths from extraneous light and light emitting elements.

  Here, in this specification, the diffusing agent means, for example, one having a center particle diameter of 1 nm or more and less than 5 μm. A diffusing agent having a size of 1 μm or more and less than 5 μm can be suitably used because it diffuses light from the light emitting element 32 and the fluorescent material well, and can suppress color unevenness that tends to occur by using a fluorescent material having a large particle size. . In addition, the half width of the emission spectrum can be narrowed, and a light emitting device with high color purity can be obtained. On the other hand, the diffusing agent having a wavelength of 1 nm or more and less than 1 μm has a low interference effect on the light wavelength from the light emitting element 32, but has a high transparency and can increase the resin viscosity without reducing the luminous intensity.

(Filler)
Furthermore, the sealing member 36 may contain a filler in addition to the fluorescent material. As a specific material, the same material as the diffusing agent can be used. However, the diffusing agent and the filler have different center particle sizes. In this specification, the center particle size of the filler is preferably 5 μm or more and 100 μm or less. When a filler having such a particle size is contained in the sealing member 36, the chromaticity variation of the light emitting device is improved by the light scattering action, and the thermal shock resistance of the sealing member 36 can be enhanced. As a result, a highly reliable light-emitting device that can prevent disconnection of the wire that electrically connects the light-emitting element and the external electrode, and peeling between the bottom surface of the light-emitting element and the bottom surface of the recess of the package, even when used at high temperatures. And can. Furthermore, the fluidity of the resin can be adjusted to be constant for a long time, and a sealing member can be formed in a desired place, enabling mass production with a high yield.

(Convex)
Moreover, in order to improve the light guide to the light visual recognition side, the convex part provided with the surface layer with a high reflectance can also be provided on the light emitting element surface in a semiconductor light emitting element. FIG. 10 is a plan view of the semiconductor light emitting element 1a. In the semiconductor light emitting device 1a of this figure, the same members as those of the semiconductor light emitting device 1 shown in FIG. The semiconductor light emitting device 1a has a plurality of convex portions 11 arranged on the surface of the n-type contact layer 13 which is an exposed surface for forming the n-type pad electrode 20a and spaced from the electrode. The convex portion 11 is provided so as to surround the semiconductor multilayer structure including the active layer. At this time, the mounting positions of the respective convex portions may be evenly spaced, or may be arranged eccentrically in consideration of the light guide path by reflection of light. Furthermore, the convex portion can have various shapes such as a circular shape, a rhombus shape, a triangular shape, and a hexagonal shape as viewed from the light emission observation surface side, and can have any number of placements. Moreover, although the top part of the convex part 11 which concerns on Embodiment 1 is the substantially same position as the light emitting layer 4 in sectional drawing in FIG.1 (b), the height is not limited to this but can be changed freely. For example, it can be made higher than the position of the light emitting layer 4. Moreover, it is good also as a shape which becomes thin gradually as it goes upwards. With such a structure, the light emitted from the light emitting layer 4 can be reflected with high efficiency toward the observation surface. Furthermore, the convex part 11 consists of a single layer or a multilayer metal, and is comprised by the reflection layer which consists of any metal of Ag, Al, Rh, these alloys, or those combinations at least in the upper layer. Or the exposed surface of the convex part 11 is coat | covered with the metal which comprises said reflection layer. Thereby, the light emitted from the light emitting layer and the reflected light in the light emitting device are reflected by the convex portion 11 toward the light observation surface, and the light extraction efficiency of the device is generally increased.

  Further, by using a mask formed in a predetermined shape such as a circle, a triangle, or a rectangle formed on the surface of the n-type contact layer, a concave portion having the predetermined shape is formed by RIE (reactive ion etching). The part 11 can also be formed. Further, the unevenness, that is, the convex portion 11 can be formed by removing other portions while leaving the predetermined shape. When unevenness is formed on the n-type contact layer, the unevenness can be formed on the interface as well as the interface between the n-type electrode and the n-type contact layer. Further, the exposed surface of the convex portion 11 is covered with a reflective layer similar to the surface / lowermost layer of the electrode.

Moreover, the height of the convex part 11 can be changed freely, for example, can also be made higher than the position of an active layer. FIG. 11 is an enlarged schematic view of the vicinity of the n-electrode 20a and the p-electrode 10a of the semiconductor light emitting device 1a in FIG. 10 (the protective film 7 is not shown). In the semiconductor light emitting device 1a of this figure, the same members as those of the semiconductor light emitting device 1 shown in FIG. The semiconductor light emitting element 1a includes a convex columnar body 11a as a convex portion for reflecting the emitted light L emitted from the light emitting layer 4 to the substantially horizontal side toward the observation surface side (upper side in FIG. 11). The convex columnar body 11a can be formed by simplifying the process if the following forming method is adopted. That is, in the manufacture of the semiconductor light emitting device 1a, after the p-type semiconductor layer 5a is stacked, a mask material, for example, SiO ₂ and a resist film are applied and exposed to a desired pattern to define the mask, and etching through the mask is performed. The part where the light emitting layer 4 functioning as a light emitting element remains, the part where the n type electrode is finally disposed on the surface of the n type semiconductor layer 3a, and the light emitting layer 4 and the p type semiconductor layer from the n type semiconductor layer 3a The convex columnar object 11a including up to 5a can be formed. Alternatively, the convex columnar body 11a may have the same member and stacked height as the constituent layers of the n-type pad electrode 20a, and both may be formed in the same process. Further, at that time, a structure in which the reflective layer 12 covering the exposed surface of the convex portion 11 is separately covered as shown in FIG. 11 may be separately provided. Preferably, the surface layer 20c has the upper surface and side surfaces of the lower layer like the coating layer 12 as shown in FIG. The covering layer 12 can be omitted by adopting a covering structure.

  With such a method for forming the convex columnar body 11a, the exposed surface for forming the n-type electrode can be formed, and the convex columnar body 11a can be formed simultaneously with the semiconductor layer or the n-type electrode, thereby simplifying the process. Is done. Further, the convex columnar body 11a can be easily formed at a position higher than the active layer, and thus the light L emitted from the active layer 4 in the side surface direction is easily reflected by the convex columnar body 11a. That is, the traveling direction of light can be changed toward the observation plane. In the semiconductor light emitting device 1a according to the present embodiment, in the convex columnar object 11a, the exposed portion, that is, the outer surface is coated with the reflective layer 12, thereby preventing the light from being absorbed into the convex columnar object 11a itself. Furthermore, since the reflectance of light can be increased, the light extraction efficiency to the observation surface side increases. The reflective layer 12 is a metal layer made of at least one of Ag, Al, and Rh, which is the same material as the reflective layers 10b, 10c, 20b, and 20c that can be formed on the upper and lower layers of the pad electrodes 10a and 20a described above. Or it is set as the single layer or multiple layer of the alloy containing this. Furthermore, it is preferable that the convex columnar body 11a is gradually narrowed from the n-type contact layer side toward the p-type contact layer side. Since the side surface of the convex columnar body 11a is inclined, the light extraction to the observation surface side can be further improved.

  Moreover, if the process of forming the convex columnar object 11a is not used as the process of forming the exposed surface for forming the n-type electrode, the height of the convex columnar object 11a is not limited to the above and can be freely set. At this time, the material of the convex columnar body 11a is not particularly limited, and includes the metal layer made of at least one of Ag, Al, and Rh that is the same as the laminated member of the semiconductor light emitting element or that constitutes the reflective layer, or includes this. It can be a single layer or multiple layers of alloys.

(Embodiment 2)
FIG. 12A is a perspective view of a light emitting device 50 according to an embodiment of the present invention. 12B is a cross-sectional view taken along line 6B-6B ′ of the light emitting device 50 shown in FIG. Hereinafter, an outline of the surface-mounted light-emitting device 50 will be described with reference to FIGS. 12 (a) and 12 (b). The light emitting device 50 includes a lead 57 and a package 57 having a space that is open in a substantially concave shape toward the top. Further, the light emitting element 52 is mounted on the exposed lead frame 54 in the space of the package 57. As the light emitting element 52 in the second embodiment, the semiconductor light emitting element 1f shown in FIG. 6 is used alone, but the type and the number of mounted semiconductor light emitting elements are not particularly limited. The package 57 is a frame that surrounds the light emitting element 52. In addition, a protective element 58 such as a Zener diode, which is energized when a voltage higher than a specified voltage is applied, can be placed in the open space of the package 57. Further, the light emitting element 52 is electrically connected to the lead frame 54 via bonding wires 55, bumps, and the like, which are conductive members. In addition, the open space of the package 57 is filled with a sealing member 56. Further, by attaching a lens made of epoxy, silicone resin, glass or the like to the surface of the sealing member 56, further directivity can be enhanced. Furthermore, a heat sink such as copper can be attached to the bottom surface of the lead frame 54 to improve heat dissipation, and a large current can be input.

  A phosphor 53 as a light scattering member contained in the package 57 is shown in FIG. 12B (the phosphor 53 in FIG. 12A is omitted). As this phosphor 53, the same phosphor as in the first embodiment can be used. The phosphor 53 has settled in the package 57 and is arranged in the vicinity of the light emitting element 52 as shown in FIG.

  In the light emitting device 50 according to the third embodiment, as in the first and second embodiments, the light loss is suppressed by the reflection layer (not shown) of the pad electrode formed in the light emitting element 52, and the light extraction is performed. Increase efficiency.

(Embodiment 3)
Furthermore, as Embodiment 3, an example of a light-emitting device in which a plurality of light-emitting elements is mounted is illustrated in FIG. The light emitting device 60 of FIG. 13 is different from the light emitting device 50 shown in FIG. 12 in terms of the number of mounted elements, but has the same structure as the others. Accordingly, similar members are denoted by the same reference numerals, and detailed description thereof is omitted. Further, in the light emitting device 60 of FIG. 13, the sealing member 56 contains the phosphor 3, but the illustration is omitted.

A light-emitting device 60 according to FIG. 13 includes three semiconductor light-emitting elements 1f shown in FIG. Further, FIG. 14 is a partially enlarged schematic view of a cross section taken along line 6A-6A ′ in FIG. Note that the semiconductor light emitting device 1f shown in FIG. 14 uses the cross-sectional view of the semiconductor light emitting device 1f shown in FIG.
In the light emitting device 60, three light emitting elements 52a, 52b, and 52c are mounted on a lead frame 54. That is, the light emitting device 60 is appropriately reflected on the outermost surface layer and the lowermost layer of the p-type pad electrode and the n-type pad electrode of each light-emitting element. A layer is provided. Further, the sealing member 56 has a distribution region of the light scattering member 33 that is unevenly distributed on the semiconductor light emitting element 1 side. However, the amount, shape, size, mounting position, etc. of the light scattering member 33 shown in FIG. 14 are simplified. An example of the traveling direction of light in the light emitting device 60 will be described with reference to FIG. The emitted light L1 from the light emitting layer 4a in one light emitting element (for example, the light emitting element 52a placed on the left side in FIG. 14) is the outermost surface layer of the p-type pad electrode of the adjacent light emitting element 52b as indicated by the arrow L1. The light is reflected by the reflective layer 10c2 formed on the light observation surface and guided to the light observation surface side. Further, as described above, a part of the light emitted from the light emitting layer 4a is reflected by a member constituting the light emitting device 60 such as the light scattering member 33 and becomes return light to the element side. This return light is guided to the light observation surface side (upper side in FIG. 14) by the reflective layers (for example, 10c1, 20c2, and 20c3) formed on the surface layers of the p-type and n-type pad electrodes. Moreover, the reflective layer (for example, 10b3) located in the lowest layer of the pad electrode suppresses the emission light L from the light emitting layer 4a from being absorbed by the electrode.

  As described above, when a plurality of light emitting elements 52a, 52b, and 52c each having a pad electrode having the reflective layer 4a are placed in the light emitting device 60, two light emitting layers 4a from the light emitting layer 4a through the light scattering member 33 and the like are used. The traveling direction of not only the secondary light but also primary light that is direct light emitted from the light emitting layer 4a can be corrected. That is, among a plurality of light emitting elements arranged in the vicinity, each other's primary light (L1 light in the figure) and secondary light (L2 light in the figure) can be guided to the light viewing side. As a result, it is possible to increase the light extraction efficiency of the light itself emitted from the light source and to increase the output of the entire apparatus. In the p-type and n-type pad electrodes shown in FIG. 14, the upper layer member is laminated so as to cover the lower layer member in the laminating direction, that is, all exposed surfaces including the upper and side surfaces of the electrode are reflected. Covered with layers. As a result, the amount of light received by the reflective layer is increased, so that the above effect is further increased. Furthermore, by mounting a plurality of elements in the light emitting device, the reflection angle of light at the interface of the sealing member 56 can be increased, so that the emitted light of the device can be made more three-dimensional.

(Surface mount type: Comparative Example 1, Examples 1 to 3)
Tables 1 and 2 show characteristics of the surface-mounted light-emitting device in which a single element is mounted as shown in FIG. The semiconductor light emitting elements mounted on the light emitting devices of Comparative Examples 1 and 2 and Examples 1 to 5 have the electrode shape shown in FIG. 6 and have a substantially square size of 800 μm × 800 μm. Specifically, an n-electrode 20a is provided in the central region of the device, and a p-pad electrode 10a is provided at both corners of one side of the device. Further, an extended conductive portion 9b extending in one direction from the n electrode 20a to the p pad electrode 10a is formed, and the p pad electrode 10a includes an extended conductive portion extended to the periphery and opposite sides of the element. . In Table 1, the pad electrode in the light emitting device of Comparative Example 1 has a laminated structure made of Ti / Rh / Au / Ni. This outermost Ni layer has the same structure (composition / film thickness) as the lowermost Ni adhesion layer described above, and functions as an adhesion layer with the protective film, for example, a 6 nm thin film layer is provided. In addition, since it is a thin film layer in the opening part of an external connection part, it is removed. Compared to Comparative Example 1, the pad electrodes of the light emitting devices of Examples 1 to 3 are composed of Ti / Rh / ASC / SiO _{2 in the} order of lamination, and have a reflective layer (ASC) on the outermost surface layer. ASC is an alloy of Al in which silicon (Si) and copper (Cu) are added to aluminum (Al). By using an alloy, migration of Al can be prevented, and the life characteristics of the light emitting device are improved. Examples 1 to 3 have the same structure except that the thickness of the electrode protective layer is different from 100 mm, 500 mm, and 1000 mm. Table 1 shows values of light output, luminous flux, forward voltage, and power efficiency in the light emitting devices of Comparative Example 1 and Examples 1 to 3 having the above conditions.

  In addition, FIG. 15 is a graph of power efficiency related to the light emitting devices of Comparative Example 1 and Examples 1 to 3, FIG. 16 is a graph of the forward voltage, FIG. 17 is a graph of the light output, and FIG. A graph of luminous flux is shown. From Table 1 and each data of FIGS. 15 to 18, the light emitting device (Examples 1 to 3) provided with the pad electrode having the reflective layer is a light emitting device having the conventional pad electrode not having the reflective layer (Comparative Example 1). It was confirmed that a high light emission output can be obtained as compared with. In particular, the light emitting device (Example 1) in which the electrode protective layer coated on the reflective layer had a small thickness showed excellent characteristics.

(Surface mount type: Comparative Example 2, Examples 4 to 5)
In addition, the characteristics of the surface mount type light emitting device (Examples 4 and 5) and the conventional light emitting device (Comparative Example 2) in which the material of the electrode protection layer that is the exposed surface of the pad electrode was changed were compared. The data is shown in Table 2. Comparative Example 2 does not have a reflective layer in the pad electrode, and has the same laminated structure as Comparative Example 1. The light emitting device according to Examples 4 and 5 has a pad electrode composed of Ti / Rh / ASC / electrode protective layer. The electrode protective layer of Example 4 is SiO ₂ , and the electrode protective layer of Example 5 is It differs in that it is made of Al ₂ O ₃ .

19 is a graph of power efficiency related to the light emitting devices of Comparative Example 2 and Examples 4 to 5, FIG. 20 is a graph of the forward voltage, FIG. 21 is a graph of the light output, and FIG. The graph of is shown. From the data in Table 2 and FIGS. 19 to 22, the light emitting device (Examples 4 to 5) having the pad electrode having the reflective layer is the light emitting device having the conventional pad electrode not having the reflective layer (Comparative Example 2). It was confirmed that a high light emission output can be obtained as compared with. Further, in the material of the electrode protective layer of the pad electrode, no difference in characteristics of the light emitting device appeared between silicon oxide (SiO ₂ ) and aluminum oxide (Al ₂ O ₃ ). That is, it is considered that the factors that improve the characteristics of the light emitting device such as the power efficiency are less dependent on the electrode protective layer and largely due to the reflective layer.

(Cannonball type: Comparative Example 3, Examples 6-8)
In addition, as shown in FIG. 8, the characteristics of the bullet-type light emitting device are shown in Tables 3 to 6. The semiconductor light emitting elements mounted on the semiconductor light emitting devices of Comparative Examples 3 to 4 and Examples 6 to 11 in the table have the electrode shape shown in FIG. 1 or FIG. 4, and both semiconductor light emitting elements are 800 μm × 800 μm. Having a substantially square size. Specifically, the characteristic evaluation shown in Table 3 relates to a bullet-type light emitting device equipped with the light emitting element according to FIG. Further, the electrode structure of Comparative Example 3 is Ti / Rh / Au / Ni in the order of lamination, Example 6 is Ti / Rh / Au / Rh, Example 7 is Ti / Rh / Au / Rh / Al, Example 8 Has an electrode structure of Ti / Rh / Au / Rh / Al / Al ₂ O ₃ . Furthermore, in order to compare the power efficiency and the characteristics in the presence or absence of the reflective layer, Table 4 shows a comparative evaluation of Examples 6 to 8 based on Comparative Example 3.

  FIG. 23 is a graph showing the light output and light flux of Comparative Example 3 and Examples 6 to 8 based on Table 3, and FIG. 24 is the power efficiency, light output ratio, light flux ratio, and power efficiency according to Table 4. It is a graph which shows ratio. From the tables and figures, the light-emitting device equipped with the element having the reflective layer is improved in all values as compared with the device not provided with the reflective layer, and the improvement of the characteristics was confirmed.

(Cannonball type: Comparative Example 4, Examples 9 to 11)
Table 5 shows the characteristic evaluation of a bullet-type light emitting device equipped with the semiconductor light emitting element according to FIG. The semiconductor light emitting elements mounted on the light emitting devices of Comparative Example 4 and Examples 9 to 11 were compared with the semiconductor light emitting elements according to Comparative Example 3 and Examples 6 to 8 in terms of electrode area, electrode arrangement, and electrode shape. Although different, the lamination material and the lamination order in the multilayer are the same. Furthermore, in order to compare the power efficiency and the characteristics with and without the reflective layer, Table 6 shows a comparative evaluation of Examples 9 to 11 with Comparative Example 4 as a reference.

  FIG. 25 is a graph showing the light output and light flux of Comparative Example 4 and Examples 9 to 11 according to Table 5, and FIG. 26 shows the power efficiency, light output ratio, light flux ratio, and power efficiency ratio of Table 6. It is a graph to show. From the tables and figures, it was confirmed that the values with the reflective layer increased in all values and improved in characteristics as compared with the light emitting device equipped with the light emitting element without the reflective layer.

  In addition, the semiconductor light emitting devices 1 and 1d in FIGS. 1 and 4 have the same shape and cross-sectional area in the cross section of the semiconductor layer in a direction substantially orthogonal to the stacking direction of the semiconductor layers, but have different electrode arrangement regions. . Specifically, as illustrated, the electrode area of the semiconductor light emitting device 1 is smaller than the electrode area of the semiconductor light emitting device 1d. In addition, since the reflective layer constitutes the uppermost layer of the electrode, the reflective layer region conforms to the electrode region. From the above comparative examples and examples, regarding the characteristics of the light emitting device in the ratio of the electrode arrangement area of the element, in the light emitting device equipped with the semiconductor light emitting element having a small electrode area, its light output value and light flux value (Table 3 and FIG. 23) Is larger than the light output value and the luminous flux value (Table 5 and FIG. 25) of the light emitting device equipped with the semiconductor light emitting element having a large electrode area. This is because the ratio of the exposed light emitting layer region increases when the electrode arrangement area is small. On the other hand, when the light output ratio, the luminous flux ratio, and the power efficiency ratio of the element with the reflective layer with respect to the absence of the reflective layer are compared in the elements having the same electrode area, the light output ratio of the element having a large electrode arrangement area The luminous flux ratio and the power efficiency ratio (Table 4, FIG. 24) were improved to the same or higher levels as compared with those of the elements having a small electrode arrangement area (Table 6, FIG. 26). That is, it was confirmed that the light output ratio, the luminous flux ratio, and the power efficiency ratio of the light emitting device in which the ratio of the reflective layer to the light emitting layer is a certain level or more are improved. In addition, when the case of the blue LED not containing the phosphor was evaluated, due to the difference in the outermost surface layer as described above, the light output and the luminous flux did not change, or only a slight increase tendency was observed. . From this, it was confirmed that the light-emitting device of this example can exhibit a synergistic effect by the combination with the phosphor and the light scattering member.

  The semiconductor light-emitting device and the method for manufacturing the semiconductor light-emitting device of the present invention can be suitably used for illumination light sources, LED displays, backlight sources, traffic lights, illumination switches, various sensors, various indicators, and the like.

FIG. 1A is an explanatory diagram of an LED according to Embodiment 1, FIG. 1A is a plan view thereof, and FIG. 1B is a cross-sectional view taken along line 1B-1B ′ of FIG. 2 is a cross-sectional view of the LED according to Embodiment 1. FIG. 6 is a plan view of another LED according to Embodiment 1. FIG. 6 is a plan view of another LED according to Embodiment 1. FIG. 6 is a plan view of another LED according to Embodiment 1. FIG. FIGS. 6A and 6B are explanatory diagrams of the LED according to Embodiment 1, in which FIG. 6A is a plan view, and FIG. 6B is a cross-sectional view taken along line 6B-6B ′ in FIG. 2 is a cross-sectional view of the LED according to Embodiment 1. FIG. 2 is a cross-sectional view of the light emitting device according to Embodiment 1. FIG. 2 is a partially enlarged view of the light emitting device according to Embodiment 1. FIG. 1 is a plan view of a semiconductor light emitting element according to a first embodiment. 1 is a partially enlarged cross-sectional schematic view of a semiconductor light emitting element according to a first embodiment. FIGS. 12A and 12B are explanatory views of the light-emitting device according to Embodiment 2, and FIG. 12A is a perspective view thereof, and FIG. 12B is a cross-sectional view taken along line 6B-6B ′ of FIG. 6 is a perspective view of a light emitting device according to Embodiment 3. FIG. FIG. 14 is a partially enlarged schematic cross-sectional view taken along line 6A-6A ′ of FIG. 13. It is a graph of the power efficiency of the light-emitting device which concerns on the comparative example 1 and Examples 1-3. It is a graph of the forward voltage of the light-emitting device which concerns on the comparative example 1 and Examples 1-3. It is a graph of the light output of the light-emitting device which concerns on the comparative example 1 and Examples 1-3. It is a graph of the light beam of the light-emitting device which concerns on the comparative example 1 and Examples 1-3. It is a graph of the power efficiency of the light-emitting device which concerns on the comparative example 2 and Examples 4-5. It is a graph of the forward voltage of the light-emitting device which concerns on the comparative example 2 and Examples 4-5. It is a graph of the light output of the light-emitting device which concerns on the comparative example 2 and Examples 4-5. It is a graph of the light beam of the light-emitting device which concerns on the comparative example 2 and Examples 4-5. It is a graph which shows the characteristic of the light-emitting device which concerns on the comparative example 3 and Examples 6-8. It is a graph which shows the power efficiency and output ratio of the light-emitting device which concerns on the comparative example 3, and Examples 6-8, luminous flux ratio, and power efficiency ratio. It is a graph which shows the characteristic of the light-emitting device which concerns on the comparative example 4 and Examples 9-11. It is a graph which shows the power efficiency and output ratio, luminous flux ratio, and power efficiency ratio of the light-emitting device which concerns on the comparative example 4 and Examples 9-11. FIG. 27A is a schematic view of a conventional semiconductor light emitting device, FIG. 27A is a plan view thereof, and FIG. 27B is a cross-sectional view taken along line B-B ′ of FIG. Sectional drawing of the conventional semiconductor light-emitting device is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1c, 1d, 1e, 1f, 100, 200 ... Semiconductor light emitting element 2 ... Growth substrate 2a ... Sapphire substrate 3 ... 1st conductivity type semiconductor layer 3a ... N-type semiconductor layer 4, 4a ... Light emitting layer 5 ... 1st Two-conductivity-type semiconductor layer 5a ... p-type semiconductor layer 6 ... translucent conductive layer 7 ... protective film 8 ... semiconductor layer 9 ... stretched conductive portion 9b ... n-type stretched conductive portion 10 ... second conductive-type electrode 10a ... p-type pad Electrodes 10b, 10b3: Lowermost reflective layer of p-type pad electrode 10c, 10c1, 10c2: Reflective layer of outermost surface layer of p-type pad electrode 11: Convex portion 11a ... Convex columnar object 12 ... Reflective layer 13 ... n-type Contact layer 14a, 14b ... external connection portion 20 ... first conductivity type electrode 20a ... n-type pad electrode 20b ... lowermost reflective layer of n-type pad electrode 20c, 20c1, 20c2, 20c3 ... outermost surface layer of n-type pad electrode Reflection Layers 30, 40 ... Light emitting device 31 ... Cup 32, 52a, 52b, 52c ... Light emitting element 33 ... Light scattering member 34 ... Lead frame 34a ... Lead frame electrode 35 ... Conductive member 36 ... Sealing member 37 ... Mold 39 ... Electrode DESCRIPTION OF SYMBOLS 50, 60 ... Light-emitting device 52 ... Light-emitting element 53 ... Phosphor 54 ... Lead frame 55 ... Bonding wire 56 ... Sealing member 57 ... Package 58 ... Protection element 101 ... Sapphire substrate 102 ... N-type nitride semiconductor layer 103 ... Light-emitting layer 104 ... p-type nitride semiconductor layer 105 ... semiconductor layer 106 ... transparent electrode 107, 108 ... pad electrode 109 ... protective film 201 ... reflective film L, L1, L2 ... emitted light

Claims (10)

A semiconductor light emitting device (1);
A light emitting device comprising a light scattering member (33) capable of reflecting or scattering light emitted from the semiconductor light emitting element (1),
The semiconductor light emitting device (1)
A first conductivity type semiconductor layer (3);
A light emitting layer (4) formed on at least a part of the first conductive semiconductor layer (3);
A second conductive type semiconductor layer (5) formed on the light emitting layer (4);
A second conductivity type electrode (10) provided on at least a part of the second conductivity type semiconductor layer (5) and supplying a current to the second conductivity type semiconductor layer (5);
Are sequentially stacked,
At least part of the first conductivity type semiconductor layer (3) is disposed on the same side as the second conductivity type electrode (10), and supplies current to the first conductivity type semiconductor layer (3). A first conductivity type electrode (20),
In the stacking direction of the semiconductor light emitting device (1), at least one of the first conductivity type electrode (20) and the second conductivity type electrode (10) is a reflective layer (20c, 10c) on the surface side. , Formed of at least two layers consisting of the first layer located on the lower layer side of the reflective layer (20c, 10c),
The reflectance of the reflective layer (20c, 10c) is higher than the reflectance of the first layer,
The reflective side of the reflective layer (20c, 10c) and the light emitting side of the semiconductor light emitting element (3) are on the same plane side, and sealed with a sealing member (36) containing the light scattering member. A light emitting device characterized by comprising: The light-emitting device according to claim 1,
The light emitting device, wherein the sealing member (36) has a distribution region of the light scattering member (33) on the semiconductor light emitting element (1) side. The light-emitting device according to claim 1 or 2,
The light-emitting device, wherein the reflective layer (20c, 10c) has a reflectance of 90% or more. The light-emitting device according to any one of claims 1 to 3,
The first conductivity type electrode and the second conductivity type electrode have external connection portions (14b, 14a) connected by a conductive member (35) that can be electrically connected to the external electrode,
The light emitting device, wherein a reflectance of the reflective layer (20c, 10c) is higher than a reflectance of the external connection portion (14b, 14a). The light-emitting device according to claim 4,
The external connection portion (14b, 14a) is formed by forming a through hole in the reflective layer (20c, 10c),
The light emitting device, wherein the first layer is exposed through the through hole. A light-emitting device according to any one of claims 1 to 5,
Further, the first conductivity type electrode (20) and the second conductivity type electrode (10) have a lowermost layer on the lower layer side of the first layer,
The lowermost layer is constituted by a reflective layer (20b, 10b),
The light emitting device according to claim 1, wherein a reflectance of the lowermost reflective layer (20b, 10b) is higher than a reflectance of the reflective layer (20c, 10c) on the surface. The light-emitting device according to claim 1,
In the stacking direction of the semiconductor light emitting device (1), the first conductivity type electrode and the second conductivity type electrode (20, 10) are formed of at least two layers,
One of the first conductivity type electrode (20) and the second conductivity type electrode (10) has a reflective layer on the surface side, and the other electrode has a reflective layer on the bottom layer,
The reflectance of the lowermost reflective layer is higher than the reflectance of the surface reflective layer,
The reflective side of the reflective layer (20c, 10c) and the light emitting side of the semiconductor light emitting element (3) are on the same plane side, and sealed with a sealing member (36) containing the light scattering member. A light emitting device characterized by comprising: The light emitting device according to any one of claims 1 to 7,
A light emitting measure comprising a plurality of the semiconductor light emitting elements (1). A light-emitting device according to any one of claims 1 to 8,
The light-emitting device, wherein the reflective layer (20c, 10c) includes a metal layer made of at least one of Ag, Al, and Rh, or a single layer or an alloy layer including the metal layer. A light emitting device according to any one of claims 1 to 9,
The light emitting device, wherein the scattering member (33) is a YAG phosphor or a LAG phosphor.

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