JP2008294265A - Semiconductor laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable semiconductor laser device by suppressing the peeling of an electrode on a ridge, thereby preventing the peeling of a wire connected to an electrode. <P>SOLUTION: In the semiconductor laser device including a laminated semiconductor including a first conductivity type semiconductor layer, an active layer and a second conductivity type semiconductor layer, a striped ridge formed on the laminated semiconductor, the electrode formed on the ridge and a resonator end face formed on the laminated semiconductor, an end face protective film coating the laminated semiconductor and the upper surface of the electrode continuously from the resonator end face is provided, and the end face protective film has a notched part on the end part on the opposite side of the resonator end face on the upper surface of the semiconductor laser device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor laser device and a method for manufacturing the same, and more particularly to an optical disk system capable of recording / reproducing and recording information such as CD / MD / DVD, and an electronic device such as a light source such as a laser printer and an optical network. The present invention relates to a semiconductor laser device and a manufacturing method thereof.

2. Description of the Related Art In recent years, semiconductor devices, particularly semiconductor laser elements, have become smaller, lighter, more reliable, and have higher output, and are used as light sources for electronic devices such as personal computers and DVDs and medical devices. Among these, group III-V nitride semiconductors are capable of emitting light at a relatively short wavelength, and are therefore actively studied for use as a light source for next-generation DVDs (for example, Patent Document 1 and Patent Document). 2).
In the semiconductor light emitting device described in Patent Document 1, the n electrode is formed on the same side as the p electrode with respect to the substrate. On the other hand, in the semiconductor laser described in Patent Document 2, the n electrode is formed on the opposite side of the p electrode with respect to the substrate.

A method for manufacturing a semiconductor laser in which an n-electrode is formed on the side opposite to the p-electrode with respect to the substrate using a nitride semiconductor will be described with reference to FIG. FIG. 6 is a cross-sectional view schematically showing a configuration of a conventional semiconductor laser element. FIG. 6 shows a state in which a bar shape is cut out from a wafer shape in which the layers of the semiconductor laser are stacked. As shown in FIG. 6, in the semiconductor laser, a nitride semiconductor layer 120 is stacked on a substrate 110 that forms a wafer. The nitride semiconductor layer 120 includes an n-type semiconductor layer 121, an active layer 122, and a p-type semiconductor layer 123 having a ridge 123a formed on the surface, which are stacked in this order. The surface of the p-type semiconductor layer 123 other than the top surface of the ridge 123a and the side surface of the nitride semiconductor layer 120 are covered with a protective film 140 made of, for example, an oxide film. A p-electrode 150 is connected to the upper surface of the ridge 123a. The p electrode 150 is formed so as to cover the upper surface of the ridge 123 a and the protective film 140. An n electrode 160 is formed on the back surface of the substrate 110. The semiconductor laser 100 shown in FIG. 6 is divided into a bar shape from a wafer shape (not shown), and is sandwiched between spacers 180 and 190 from above and below, the front (light extraction surface) side and the rear (back surface) side. A protective film is formed on the end face of the substrate. The protective film formed in this step is for causing the front and rear resonator end faces to function as mirrors. After the end face protective film as a mirror is formed, the bar-shaped semiconductor laser is cleaved into a chip shape, and a wire is connected to the ridge peripheral portion 150b formed outside the ridge just above the ridge 150a on the upper surface of the p-electrode 150. (Wire bonding), a semiconductor laser device is manufactured.
JP 2000-12970 A (paragraphs 0016-0020, FIG. 1) JP 2006-128558 A (paragraph 0014, FIG. 1)

In a nitride semiconductor laser element, a ridge is usually formed on the surface of a semiconductor layer, and an electrode is formed on the ridge. The width of the ridge is very thin, from less than 1 μm to about 10 μm, and the requirement tends to become more severe in the case of a laser device that obtains single-mode light. In order to form an electrode on such a thin ridge, a plurality of processes such as film formation of a mask for electrode formation, patterning, film formation of an electrode, lift-off, etc. are required, and high-precision processing is performed in each process. Technology is required. In addition, depending on the electrode material used, the electrode may be peeled off during the process due to poor adhesion between the electrode and the semiconductor layer or the protective film. Even if the electrode is formed on the ridge, the electrode may be peeled off due to an external load or stress applied to the wafer during the subsequent steps such as elementization and mounting. The same problem may occur not only in the ohmic electrode but also in the pad electrode. Further, in a semiconductor laser element, the electrode may be peeled off during driving of the element due to the influence of the element stress, current and heat. There is a greater concern about the influence of heat when a high current is passed or when driving for a long time. Such electrode peeling often occurs from the end of the electrode, and is likely to be a problem. Since the operation of the element becomes unstable due to the peeling of the electrode and affects the element characteristics and reliability, it is necessary to prevent the peeling of the electrode.
In the semiconductor laser element, an end face protective film is formed on the end face of the resonator. However, if the end face protective film wraps around the p-electrode, there is a problem that even if wire bonding is performed, the wire is peeled off.
The present invention has been made in view of the above problems, and provides a highly reliable semiconductor laser device by suppressing peeling of an electrode on a ridge and preventing peeling of a wire connected to the electrode. Objective.

In order to solve the above problems, a semiconductor laser device according to the present invention includes a stacked semiconductor including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, and a stripe-shaped ridge formed in the stacked semiconductor. In the semiconductor laser device having an electrode formed on the ridge and an end face of the resonator formed in the laminated semiconductor, end face protection for covering the laminated semiconductor and the upper surface of the electrode continuously from the end face of the resonator The end face protective film has a notch at the end opposite to the resonator end face on the upper surface of the semiconductor laser element.
According to such a configuration, since the end face protective film covers the upper surface of the electrode continuously from the cavity end face, the semiconductor laser element can prevent peeling from the end of the electrode and protect the end face. Since the notch portion is provided at the end portion of the film, it is possible to prevent the end face protective film from entering the wire bonding portion of the p-electrode.

According to another aspect of the semiconductor laser element of the present invention, there is provided a stacked semiconductor including a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer, a striped ridge formed in the stacked semiconductor, In a semiconductor laser device having an electrode formed on a ridge and a resonator end face formed on the laminated semiconductor, an end face protective film covering the laminated semiconductor and the upper surface of the electrode continuously from the resonator end face The end face protective film has a first region and a second region in order from the resonator end face side on the upper surface of the semiconductor laser element, and the end face protective film of the second region is formed of the first region. The lateral width is narrower than the end face protective film.
According to such a configuration, in the semiconductor laser element, since the end surface protective film continuously covers the upper surface of the electrode from the resonator end surface, it is possible to prevent peeling from the end portion of the electrode and the second Since the width of the end face protective film in the region is narrow, the region capable of wire bonding and wire bonding can be increased.

In the semiconductor laser device of the present invention, an insulating film is formed on the surface of the laminated semiconductor, the electrode is formed from the ridge to the insulating film, and the upper surface of the electrode is formed from the upper surface of the ridge. Also, it is preferable that the top surface of the insulating film is high.
According to such a configuration, it is possible to prevent the end face protective film from being excessively wrapped around the electrode formed in the portion immediately above the insulating film. Therefore, if a wire is connected to the electrode formed immediately above the insulating film, the wire can be prevented from peeling off.

In the semiconductor laser device of the present invention, the insulating film has at least a first insulating film and a second insulating film, and the first insulating film covers the surface of the stacked semiconductor separated from the ridge by a predetermined distance. The second insulating film preferably covers the side surface of the ridge, the surface of the stacked semiconductor exposed between the ridge and the first insulating film, and the first insulating film.
According to such a configuration, since the interface of the electrode on the laminated semiconductor side of the semiconductor laser element is only the second insulating film except for the ridge portion, the interface between the electrode and another member such as an adhesive film other than the second insulating film Compared with the case where there is, adhesion between the electrode and the second insulating film is improved. Furthermore, there is no need to form an extra member such as an adhesive film, and the manufacturing efficiency is improved.

In the semiconductor laser device of the present invention, the second insulating film directly covers the surface of the laminated semiconductor exposed between the ridge and the first insulating film, and the second insulating film is the first insulating film. And an upper surface of the electrode is formed such that the upper surface of the ridge is higher than the upper surface of the ridge peripheral portion, and the upper surface of the device peripheral portion is higher than the upper surface of the ridge. It is preferable that the height is high.
The semiconductor laser element of the present invention preferably has the notch on the peripheral edge of the element.
In the semiconductor laser device of the present invention, the second region has an end face protective film portion and an electrode exposed portion, and the end face protective film portion is formed immediately above the ridge and at the ridge peripheral portion. Is preferred.
According to these structures, since the lowest ridge peripheral portion on the upper surface of the electrode is provided between the highest element peripheral portion on the upper surface of the electrode and the ridge directly above, the end surface protective film is formed in the step of forming the end surface protective film. Can be prevented from being excessively wrapped around the upper surface of the electrode at the periphery of the element, and a notch portion of the electrode can be provided, or a second region of the end face protective film can be provided.

In the semiconductor laser device of the present invention, the length of the end face protective film from the resonator end face to the opposite end is formed so that the portion immediately above the ridge and the ridge peripheral portion are longer than the peripheral portion of the element. Is preferred.
Further, it is preferable that the end face protective film is formed so that the portion immediately above the ridge and the peripheral portion of the ridge are thicker than the peripheral portion of the element.
According to these structures, peeling of the electrode end can be more effectively prevented.

In the semiconductor laser device of the present invention, it is preferable that the first insulating film and the second insulating film are made of the same material.
According to this configuration, the semiconductor laser device has good adhesion at the interface between the first insulating film and the second insulating film, and the yield is further improved.

  According to the present invention, since the end face protective film covers the upper surface of the electrode continuously from the resonator end face, peeling from the end of the electrode can be suppressed, and at the end of the end face protective film. Since the cutout portion is provided, it is possible to prevent the end face protective film from wrapping around the wire bonding portion of the p-electrode, prevent non-attachment of the wire connected to the electrode, and obtain a highly reliable semiconductor laser device. it can.

The best mode for carrying out the semiconductor laser device and the manufacturing method thereof according to the present invention (hereinafter referred to as “embodiment”) will be described in detail below with reference to the drawings.
(Embodiment 1)
[Configuration of semiconductor laser element]
FIG. 1 is a cross-sectional view schematically showing a configuration of a semiconductor laser device according to an embodiment of the present invention. As shown in FIG. 1, the semiconductor laser device according to the present embodiment mainly includes a substrate 10, a nitride semiconductor layer 20 stacked on the substrate 10, a ridge 23a formed on the nitride semiconductor layer, The first insulating film 41, the second insulating film 42, a p-electrode 50, an n-electrode 60, and an end face protective film (not shown) formed on the nitride semiconductor layer. FIGS. 3B and 3B are top views schematically showing the configuration of the semiconductor laser device according to the embodiment of the present invention. As shown in FIG. 3, the semiconductor laser device according to this embodiment mainly includes a ridge 23a formed on a nitride semiconductor layer, a p-electrode 50, an end face protective film 100, and a cutout portion 101 of the end face protective film. Have FIG. 4 is an enlarged view of the vicinity of the cavity end face of the semiconductor laser device according to the embodiment of the present invention. (Α) Immediately above the ridge, (β) The ridge periphery, (γ) The device periphery It is an enlarged view which shows a cross section. FIG. 4 (α) shows the α sectional view of FIG. 3 (b), FIG. 4 (β) shows the β sectional view, and FIG. 4 (γ) shows the γ sectional view.

(substrate)
The substrate 10 is made of a nitride semiconductor (for example, GaN, AlN, AlGaN, InGaN, etc.). Note that a different substrate from the nitride semiconductor may be used. Examples of the heterogeneous substrate include, for example, an insulating substrate such as sapphire, spinel (MgA1 ₂ O ₄ ) having any one of the C-plane, R-plane, and A-plane, SiC (including 6H, 4H, and 3C), A nitride semiconductor such as an oxide substrate lattice-matched with ZnS, ZnO, GaAs, Si, and a nitride semiconductor can be grown, and a conventionally known substrate material can be used. The substrate 10 is preferably a substrate having an off angle formed on the main surface and / or the back surface.

(Nitride semiconductor layer)
The nitride semiconductor layer 20 is made of, for example, a gallium nitride compound semiconductor (eg, GaN, AlGaN, InGaN, etc.), and the n-type semiconductor layer 21, the active layer 22, and the p-type semiconductor layer 23 are arranged in this order from the substrate 10 side. It is configured by stacking. In addition, the nitride semiconductor layer 20 is represented by a general formula In _x Al _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). The n-type semiconductor layer 21 is made of, for example, GaN containing Si, Ge, O, or the like as an n-type impurity. The active layer 22 is made of InGaN, for example. The p-type semiconductor layer 23 is made of, for example, GaN containing Mg as a p-type impurity. In the present embodiment, the stacked semiconductor will be described as the nitride semiconductor layer 20, the first conductive semiconductor layer as the n-type semiconductor layer 21, and the second conductive semiconductor layer as the p-type semiconductor layer 23.

(ridge)
On the upper surface of the p-type semiconductor layer 23, a striped ridge 23a is formed so as to protrude. The width of the ridge 23a is not particularly limited, but is preferably about 0.5 to 20 μm, and more preferably about 1 to 2 μm when a single spot light source is used. The height of the ridge 23a can be appropriately adjusted depending on the film thickness of the p-type semiconductor layer 23. For example, the height is preferably about 0.2 to 2 μm, and more preferably about 0.3 to 0.8 μm.

(Insulating film)
The insulating film 40 is preferably formed on the surface of the laminated semiconductor so as to cover at least the side surface of the ridge and the surface of the p-type semiconductor layer. Furthermore, the insulating film in the present embodiment preferably has at least a two-layer structure of a first insulating film and a second insulating film. In addition to the first insulating film and the second insulating film, an insulating film may be formed to have a multilayer structure of three or more layers. As a material for the insulating film, an insulating material is preferable, and an oxide film is particularly preferable. Specifically, it consists of a Zr oxide film (ZrO ₂ ) or SiO ₂ . From another viewpoint, the insulating film preferably has a refractive index lower than that of the p-type semiconductor layer 23.

The insulating film 40 is formed by, for example, sputtering, ECR (Electron Cyclotron Resonance) sputtering, CVD (Chemical Vapor Deposition), ECR-CVD, ECR-one plasma CVD, vapor deposition, It can be formed by a known method such as an EB method (Electron Beam). Especially, it is preferable to form by ECR sputtering method, ECR-CVD method, ECR one plasma CVD method, etc.
(First insulation film)
The first insulating film 41 is formed so as to cover the surface of the p-type semiconductor layer 23 that is separated from the ridge 23 a of the p-type semiconductor layer 23 by a predetermined distance.

(Second insulating film)
The second insulating film 42 covers the side surface of the ridge 23 a of the p-type semiconductor layer 23, the surface of the p-type semiconductor layer 23 exposed between the ridge and the first insulating film, and the first insulating film 41. Yes.
The second insulating film 42 is formed of the same material as the first insulating film 41. Here, the same material means that, for example, if the first insulating film 41 is formed of a Zr oxide film, the second insulating film 42 is also formed of a Zr oxide. May cause slight differences in the composition.

(P electrode)
The p electrode 50 is formed on the upper surface of the ridge 23 a of the p-type semiconductor layer 23 so as to be electrically connected. The p-electrode 50 is preferably configured with at least a two-layer structure of a p-electrode first layer and a p-electrode second layer stacked on the p-electrode first layer. The p-electrode first layer functions as an ohmic electrode in direct contact with the p-type semiconductor layer 23. The p-electrode second layer is the uppermost layer of the p-electrode and functions as a pad electrode to which a wire is bonded. In addition, it is good also as a structure which laminated | stacked another layer between the said p electrode 1st layer and p electrode 2nd layer. The p electrode 50 is connected to the upper surface of the ridge 23a of the p-type semiconductor layer 23 and is formed from the ridge to the insulating film. The upper surface of the electrode is formed so that the upper surface of the insulating film is higher than the upper surface of the ridge. ing. Further, the upper surface of the p-electrode 50 is formed such that the upper surface 50a of the ridge is higher than the upper surface 50b of the ridge peripheral portion, and the upper surface of the second insulating film 42 on the first insulating film 41 (element). The peripheral surface 50c) is formed higher.

  The shapes of the p-electrode first layer and the p-electrode second layer are not particularly limited, and the p-electrode first layer and the p-electrode second layer may be the same shape or different shapes. The p-electrode may be formed up to the resonator end surface, or may be formed so as to be separated from the resonator end surface. In order to more effectively prevent peeling of the electrode, it is preferable to increase the contact area between the end face protective film by separating the electrode from the resonator end face so that the end face protective film is in contact with the surface of the semiconductor layer. Moreover, in order to prevent electrode peeling at the time of cleavage, it is preferable that it is spaced apart from the resonator end face.

The p-electrode first layer can be exemplified by a material that can be normally used as an electrode. For example, nickel (Ni), platinum (Pt), gold (Au), palladium (Pd), rhodium (Rh), titanium (Ti), hafnium (Hf), vanadium (V), niobium (Nb), molybdenum (Mo) ), Tungsten (W), copper (Cu), silver (Ag), and other metals, alloys; single layer films or laminated films of conductive oxides such as ITO, ZnO, and SnO ₂ .
For the p-electrode second layer, for example, Au or a Ni—Ti—Au-based electrode material can be used.

  Specific examples of the p electrode include Pt / Au, Pd / Au, Rh / Au, Ni / Au, etc. in the case of a two-layer structure of p electrode first layer / p electrode second layer. In addition, as a three-layer structure having a third layer between the p-electrode first layer and the p-electrode second layer, there are Ni / Pt / Au, Pd / Pt / Au, Rh / Pt / Au, and the like.

(N electrode)
The n electrode 60 is formed so as to be electrically connected to the back surface of the substrate 10. The n-electrode 60 is made of, for example, a metal such as Ti / Al, Ti / Pt / Au, Ti / Al / Pt / Au, W / Pt / Au, V / Pt / Au, and Hf from the back side of the substrate 10. Is done. The n-electrode 60 may be composed of an ohmic electrode and a pad electrode.

(End face protection film)
The end face protective film (mirror) covers the surface of the laminated semiconductor including the ridge continuously from the resonator end face. Moreover, the edge part of the electrode (p electrode) formed on the ridge is covered.
Examples of the material for the end face protective film include Si, Mg, Al, Hf, Nb, Zr, Sc, Ta, Ga, Zn, Y, B, Ti, and other oxides and nitrides (for example, AlN, AlGaN, GaN, BN etc.) or fluorides. The end face protective film may be formed of either a single layer structure or a laminated structure. Specifically, a single layer of an Si oxide, a single layer of an Al oxide, a stacked structure of an Si oxide and an Al oxide, or the like can be given. In addition, the material, film thickness, stacking period, and the like may be different on the emission side and the reflection side. As the end face protective film on the reflection side, for example, a stacked structure of Si oxide and Zr oxide, a stacked structure of Al oxide and Zr oxide, a stacked structure of Si oxide and Ti oxide. Examples thereof include a structure, a laminated structure of Al oxide, Si oxide, and Zr oxide, and a laminated structure of Si oxide, Ta oxide, and Al oxide. The stacking period and the like can be adjusted as appropriate according to the desired reflectance.
The end face protective film may be formed on at least one of the opposing resonator end faces, and may be formed on both the emission side and the reflection side. Further, when formed on both resonator end faces, either one may be formed so as to cover the surface of the laminated semiconductor. Further, it is not necessary to cover the end portion of the p electrode over the entire width direction of the p electrode, and it is sufficient that the end portion of the electrode is covered at least at the ridge immediately upper portion 50a. The end face protective film covers the resonator surface formed on the nitride semiconductor layer, but does not necessarily cover the entire resonator surface, and at least covers the optical waveguide region of the resonator surface. Anything to do.
The end face protective film can be formed by a known method such as a sputtering method, an ECR sputtering method, a CVD method, an ECR-CVD method, an ECR one plasma CVD method, an evaporation method, or an EB method. Especially, it is preferable to form by ECR sputtering method, ECR-CVD method, ECR one plasma CVD method, etc.

(Notch, second area)
In the present invention, on the upper surface of the semiconductor laser element, the end face protective film has a notch 101 at the end opposite to the resonator end face. The end surface protective film has a first region and a second region in order from the resonator end surface side on the upper surface of the semiconductor laser element, and the end surface protective film in the second region is an end surface protective member for the first region. The lateral width is narrower than the film. That is, as shown in FIG. 3B, the first region 100a is formed substantially continuously in the lateral direction (direction perpendicular to the resonator direction) of the semiconductor laser element, and in the second region 100b, The width in the lateral direction is narrower than the end face protective film in the first region.
In the first region 100a on the resonator end face side, an end face protective film is formed over substantially the entire width direction of the semiconductor laser element. The second region 100b having a narrow end face protective film formed on the side opposite to the end face of the resonator has a notch portion of the end face protective film on the side portion of the element. The exposed electrode exposed portion. Thereby, it is possible to prevent the end face protective film from wrapping around the wire bonding portion of the p-electrode and to prevent adhesion of the wire. Further, the area where wire bonding can be performed can be increased. In particular, when the semiconductor laser device is downsized, the area of the electrode that can be formed on the upper surface of the device is reduced, so that the area that can be used for wire bonding is also reduced. Providing a notch (electrode exposed part) in the end face protective film on the upper surface of the element is useful because the degree of freedom in bonding position on the electrode is increased and the degree of freedom in element design is increased. Further, by increasing the bonding area, it is possible to suppress the occurrence of non-bonding of the wire due to the deviation of the bonding position, and to improve the manufacturing yield. In addition, if a notch (electrode exposed portion) is formed in the end face protective film, the bonding area can be increased. Therefore, a first region having a wider width and a second region having a smaller width are formed in order from the resonator end face side. In addition, a wider area may be formed.

  If the cut-out part (electrode exposed part) and the second region of the end face protective film as described above are provided on one of the end face protective films on the emission side and the reflection side as shown in FIG. Good. Preferably, as shown in FIG. 3 (b) ′, it is provided on both resonator end faces. Moreover, the notch part (electrode exposed part) may be provided only on one side in the upper surface of the element, or may be provided on both side parts. The shape of the notch is not particularly limited, and is formed by a polygon such as a triangle or a rectangle, a circle, an ellipse, or the like.

[Method for Manufacturing Semiconductor Laser Element]
A method of manufacturing the semiconductor laser device shown in FIG. 1 will be described with reference to FIGS. 2 and 3 (refer to FIGS. 1 and 4 as appropriate). FIG. 2 is a cross-sectional view schematically showing a manufacturing process of the semiconductor laser element shown in FIG. FIG. 3 is a top view schematically showing the configuration and manufacturing process of the semiconductor laser device according to the embodiment of the present invention.
First, the n-type semiconductor layer 21, the active layer 22, and the p-type semiconductor layer 23 are stacked in this order on the wafer-shaped substrate 10 to form the nitride semiconductor layer 20.

  Next, a part of the nitride semiconductor layer 20 is etched so that the surface of the n-type semiconductor layer 21 is exposed using a mask having a desired shape so that individual semiconductor laser elements are formed. Here, the width of the laser element is preferably about 100 to 600 μm, and the etching depth is preferably about 1.5 to 3 μm. This step can be omitted.

  Next, a striped ridge 23 a is formed in the p-type semiconductor layer 23 by photolithography and etching processes. Here, the width of the ridge is preferably about 1.2 to 2 μm, and the height is preferably about 0.3 to 0.8 μm.

  Next, as shown in FIG. 2A, the first insulating film 41 is patterned on the surface of the p-type semiconductor layer 23 by ECR sputtering. The pattern shape is, for example, a substantially stripe shape parallel to the ridge. Here, the film thickness of the first insulating film 41 is preferably about 3000 to 6000 mm (angstrom). The width of the first insulating film 41 depends on the width of the semiconductor laser element, but is preferably 30 μm or more. When the width of the semiconductor laser element is 200 μm or more, the width of the first insulating film 41 is preferably 80 μm or more. In addition, since wire bonding is performed on an element peripheral portion 50c, which will be described later, the width of the wire bondable region is substantially the same as the width of the first insulating film. The width of the p-type semiconductor layer exposed between the ridge and the first insulating film is preferably about 5 to 15 μm, and particularly preferably about 5 to 10 μm. Further, the left and right side surfaces of the p-type semiconductor layer 23 and the active layer 22 and the left and right side surfaces of the n-type semiconductor layer 21 may be covered with the end portions of the first insulating film 41.

  Subsequently, as shown in FIG. 2B, on the side surface of the ridge 23a, the surface of the p-type semiconductor layer 23 exposed between the ridge 23a and the first insulating film 41, and the surface of the first insulating film 41. The second insulating film 42 is formed with a film thickness of about 1000 to 3000 mm by ECR sputtering. At this time, the height from the upper surface of the first insulating film 41 to the upper surface of the second insulating film 42 on the first insulating film 41 is preferably 4000 mm or more, and more preferably about 4000 to 5000 mm. . The second insulating film 42 is preferably formed in a concave shape between the side surface of the ridge 23a and the side surface of the first insulating film 41, and the width of the concave shape portion is preferably 10 μm or less. At this time, the upper surface of the second insulating film 42 on the first insulating film 41 is formed to be higher than the upper surface of the ridge 23a. The height from the upper surface of the ridge 23a to the upper surface of the second insulating film 42 on the first insulating film 41 is preferably 500 mm or more, more preferably about 500 to 2500 mm, and particularly about 1000 mm. Preferably there is. The reason is that if the second insulating film 42 is thicker than 2500 mm, kinks are likely to occur. The second insulating film may cover the left and right side surfaces of the nitride semiconductor layer 20 or may be formed to cover the first insulating film 41 that covers the left and right side surfaces of the nitride semiconductor layer 20. May be.

  Next, as shown in FIG. 2C, a p-electrode first layer and a p-electrode second layer are stacked on the upper surface of the ridge 23a and the upper surface of the second insulating film 42 by magnetron sputtering. An electrode 50 is formed. At this time, as described above, the second insulating film is formed such that the upper surface of the second insulating film 42 on the first insulating film 41 is higher than the upper surface of the ridge 23a. Therefore, when the p-electrode is stacked, the upper surface of the p-electrode 50 is formed so as to be higher on the second insulating film 42 on the first insulating film 41 than on the portion directly above the ridge 23a. In addition, since wire bonding is performed on the element peripheral portion 50c described later, the width of the p-electrode 50 in the element peripheral portion is preferably 30 μm or more. A top view of the semiconductor laser device shown in FIG. 2C is shown in FIG.

  Then, after forming the p-electrode 50, annealing is performed in an air atmosphere or an oxygen atmosphere, the back surface of the substrate 10 is polished, and the n-electrode 60 is formed on the polished surface. Thereafter, the wafer shape is divided into bar shapes. At this time, a step is formed on the upper surface of the p-electrode 50 as shown in FIG. That is, on the upper surface of the p-electrode 50, ridge peripheral portions 50b lower than the ridge directly upper portion 50a are formed on both outer sides of the ridge directly upper portion 50a. The first insulating film 41 is not laminated under the ridge peripheral portion 50b. Furthermore, element peripheral portions 50c are formed on both outer sides of the ridge peripheral portion 50b. A first insulating film 41 is stacked under the element peripheral edge portion 50c.

  Next, the semiconductor laser is divided from a wafer shape into a bar shape. At this time, the resonator length of the laser element is preferably about 200 to 1200 μm. As shown in FIG. 2D, the semiconductor laser divided into bar shapes is sandwiched by spacers 80 and 90 from above and below to form an end face protective film. As a result, an end face protective film is formed from the resonator end face to the semiconductor layer surface, and the end face of the electrode is covered with the end face protective film. Further, on the upper surface of the semiconductor laser element, the end face protective film has a notch at the end opposite to the resonator end face, in other words, a second region having a narrow width of the end face protective film can be formed. In the notch, the previously formed electrode is exposed. The size of the notch on the upper surface of the semiconductor laser element is such that the length in the resonator direction (that is, the length of the second region 100b) is about 5 to 10 μm, and the length in the width direction of the laser element is 15 to 30 μm. It is preferable that it is a grade. As will be described later, the length in the width direction of the notch can be determined by the width of the peripheral edge of the element. The length of the end face protective film on the upper surface of the semiconductor laser element from the resonator end face to the end of the end face protective film is about 15 to 30 μm immediately above the ridge and around the ridge. The length of the first region 100a is preferably about 10 to 20 μm. Further, the film thickness of the end face protective film on the surface of the semiconductor laser element is preferably about 500 to 800 mm at the ridge immediately above and around the ridge, and about 300 to 500 mm at the edge of the element. 3B and 3B ′ are top views of the semiconductor laser device shown in FIG.

Then, the semiconductor laser element can be obtained by cleaving from the bar shape to the chip shape and connecting the wire 70 on the peripheral portion 50c of the semiconductor laser element having the chip shape. Since the portion immediately above the ridge and the peripheral portion of the ridge are fragile, it is preferable to connect the wire 70 on the peripheral portion 50c in consideration of the influence of the impact upon bonding on the element. Since the electrode exposed portion is formed in the second region, a region capable of wire bonding can be increased.

In the present embodiment, since the upper surface of the p-electrode 50 is formed higher in the portion (element peripheral portion) immediately above the second insulating film 42 on the first insulating film 41 than in the portion immediately above the ridge 23a. The upper spacer 80 does not contact the electrode immediately above. That is, a cavity is formed between the electrode immediately above the ridge and the upper spacer, and an end face protective film is formed on the ridge so as to surround the cavity (FIG. 3 (b) cross section α, FIG. 4 (α)). Therefore, the end portion of the electrode on the ridge can be covered, and peeling of the electrode from the end portion can be prevented. Moreover, the film thickness of the end face protective film is formed to be thicker than that of the element peripheral edge as compared with the element peripheral edge, and the peeling of the electrode end can be effectively suppressed. Similarly, end face protective films are formed on the peripheral portions on both sides of the ridge. (See Fig. 3 (b) β cross section, Fig. 4 (β)) Not only on the ridge, but also on the periphery of the ridge, the end face protection film is wrapped around to cover the electrode, so that the electrode can be peeled off more effectively. Can be prevented.
At this time, the upper spacer 80 abuts on the element peripheral portion 50c on the upper surface of the p electrode 50, so that the end face protective film wraps around the element peripheral portion 50c (outside the peripheral portion) on the upper surface of the p electrode 50. The amount is smaller than that immediately above the ridge or the periphery of the ridge (see FIG. 3 (b) γ cross section, FIG. 4 (γ)). In other words, the length of the end face protective film that wraps around becomes shorter and the film thickness becomes thinner. Therefore, in the vicinity of the resonator end face, an end face protective film is formed on the periphery of the element to form the first region 100a. On the other hand, in the second region, the end face protective film that covers the electrodes is formed immediately above the ridge and in the periphery of the ridge as described above. Therefore, the end face protective film has a shape having a notch on the surface of the semiconductor laser element on the peripheral edge of the element, and the second region 100b having a narrow width of the protective film is formed on the side opposite to the cavity end face.
Thus, the end face protective film and the notch are formed on the surface of the semiconductor laser element, thereby contributing to the non-attachment of the end face protective film on the upper surface of the p-electrode 50 at the peripheral portion of the element where the wire is formed. The level can be neglected. The width of the periphery of the element at this time is the width of the notch.
In addition, in the laser element with a protruding ridge portion as shown in FIG. 6A, it is necessary to provide a margin in order to reduce the load on the fragile ridge portion when sandwiched from above and below by a spacer. Therefore, when the end face protective film is formed, as shown in FIG. 6B, the end face protective film goes around, and the notch portion of the end face protective film is not formed on the surface of the semiconductor laser element. However, in the laser element of the present invention, since the ridge portion does not contact the spacer, the end face protective film can be prevented from wrapping around the bonding portion, that is, the notch portion of the end face protective film can be formed. It becomes possible to sandwich the laser element.
Further, since the semiconductor laser element 1 has the second insulating film 42 having a lower refractive index than the p-type semiconductor layer 23 formed on the side surface of the ridge 23a, the light confinement effect in the side surface direction of the ridge is high.

  In addition, according to the method of manufacturing a semiconductor laser device of this embodiment, the upper surface of the p-type semiconductor layer 23 separated from the ridge 23a by a predetermined distance is covered with the first insulating film 41, and then from the ridge side surface excluding the ridge upper surface. The bottom surfaces on both sides of the ridge and the first insulating film 41 are covered with a second insulating film 42. As a result, the interface between the p electrode 50 and the nitride semiconductor layer 20 is only the upper surface of the ridge, and the other region is only one interface with the second insulating film 42. Therefore, the adhesion between the p-electrode 50 and the second insulating film 42 is improved.

(Embodiment 2)
[Configuration of semiconductor laser element]
FIG. 5 is a cross-sectional view schematically showing the configuration of the semiconductor laser device according to the embodiment of the present invention. As shown in FIG. 5, the semiconductor laser device according to the present embodiment mainly includes a substrate 10, a nitride semiconductor layer 20 stacked on the substrate 10, a ridge 23a formed on the nitride semiconductor layer, Consists of a protrusion 23b formed of a semiconductor layer, an insulating film 40, a p-electrode 50, an n-electrode 60, and an end face protective film (not shown) formed on the nitride semiconductor layer.
In the present embodiment, the convex portion 23b formed of the semiconductor layer is provided at a position away from the ridge by a predetermined distance, and the upper surface of the electrode of the element peripheral portion 50c is formed to be higher than immediately above the ridge. Thus, as in the first embodiment, the upper surface of the semiconductor laser element has the second region in which the width of the end face protective film is narrow, and has a notch at the end opposite to the resonator end face. . Therefore, it is possible to suppress problems due to the non-bonding of the wires while preventing the electrodes from peeling off immediately above the ridge.
(Convex)
The convex portion 23b is formed on the surface of the p-type semiconductor layer 23 that is separated from the ridge 23a of the p-type semiconductor layer by a predetermined distance.
(Insulating film)
In the present embodiment, the insulating film 40 is formed so as to cover the side surface of the ridge and the surface of the p-type semiconductor layer 23. Also in this embodiment, the insulating film 40 may be composed of two or more layers. In the present embodiment, the first insulating film formed at a predetermined distance from the ridge 23a is not formed. However, as described above, the first insulating film is formed on the insulating film by forming the convex portion 23b. The upper surface of the electrode is formed so that the upper surface of the electrode at the periphery of the element is higher by the thickness of the insulating film.

[Method for Manufacturing Semiconductor Laser Element]
A method for manufacturing the semiconductor laser element shown in FIG. 5 will be described.
The process is the same as in the first embodiment until a part of the nitride semiconductor layer 20 is etched until the surface of the n-type semiconductor layer 21 is exposed.

Next, a striped ridge 23 a is formed in the p-type semiconductor layer 23 by photolithography and etching processes. The width and height of the ridge are preferably formed in the same manner as in the first embodiment. At this time, a mask having a desired shape (for example, a substantially striped shape parallel to the ridge) is formed at a position away from the ridge by a predetermined distance to form the convex portion 23b of the semiconductor layer.
The width of the convex portion 23b depends on the width of the semiconductor laser element, but is preferably 30 μm or more. Further, when the width of the semiconductor laser element is 200 μm or more, the width of the convex portion 23b is preferably 80 μm or more. Further, since wire bonding is performed on the element peripheral edge portion 50c, the width of the wire bondable region is substantially the same as the width of the convex portion 23b. The width of the p-type semiconductor layer between the ridge 23a and the convex portion 23b is preferably about 5 to 15 μm, and particularly preferably about 5 to 10 μm.

  Subsequently, the insulating film 40 is formed with a film thickness of about 1000 to 3000 mm on the surface other than the side surface of the ridge 23a and the upper surface of the ridge 23a of the p-type semiconductor layer 23 by ECR sputtering. In addition, the insulating film has a concave portion formed between the side surface of the ridge 23a and the side surface of the convex portion 23b, and the width of the concave portion is preferably 10 μm or less. Further, the upper surface of the insulating film 40 on the convex portion 23b is formed to be higher than the upper surface of the ridge 23a. The height from the upper surface of the ridge 23a to the upper surface of the insulating film 40 on the convex portion 23b is preferably 500 mm or more, more preferably about 500 to 2500 mm, and particularly preferably about 1000 mm. . The reason is that if the insulating film 40 is thicker than 2500 mm, kinks are likely to occur. Further, when the convex portion 23b is formed simultaneously with the ridge 23a, the upper surface of the ridge and the upper surface of the convex portion can be made the same height. Therefore, when the insulating film 40 is formed, the upper surface can be increased by the thickness of the insulating film. The insulating film may cover the left and right side surfaces of the nitride semiconductor layer 20.

Thereafter, it can be formed in the same manner as in the first embodiment. Also in the present embodiment, as in the first embodiment, in the end face protective film formed on the surface of the semiconductor layer, a second region having a narrow lateral width is formed, and a notch is formed at the end opposite to the resonator end face. Since it has a portion, it is possible to suppress problems caused by non-attachment of wires while preventing peeling of the electrode immediately above the ridge.

  As mentioned above, although each embodiment was described, this invention is not limited to this, It can implement variously in the range which does not change the meaning. For example, the semiconductor laser element in which the n-electrode 60 is formed on the opposite side of the p-electrode 50 with the substrate 10 as a reference has been described. However, the present invention is not limited to this, and the n-electrode 60 is a p-electrode with reference to the substrate. It may be formed on the same side as 50. Further, the material constituting the semiconductor laser element is not limited to the nitride semiconductor. Note that the thicknesses and lengths of the constituent elements and the like shown in the drawings are exaggerated for clearly explaining the arrangement, and are not limited thereto.

Example 1
In order to confirm the effect of the present invention, a semiconductor laser device was manufactured using the method for manufacturing a semiconductor laser device according to the first embodiment. Specifically, the semiconductor laser device 1 was manufactured according to the manufacturing process shown in FIGS. In order to manufacture the semiconductor laser device 1, a wafer-shaped GaN substrate was used as the substrate 10. Then, the following layers were stacked as the nitride semiconductor layer 20 on the GaN substrate. First, an n-type cladding layer made of Si-doped AlGaN and an n-type light guide layer made of GaN were grown on a GaN substrate. Thereby, the n-type semiconductor layer 21 was formed. Subsequently, a barrier layer composed of In _0.05 Ga _0.95 N and a well layer composed of In _0.1 Ga _0.9 N are alternately stacked twice, and a multiple quantum well structure (Multi-Quantum Well: MQW) active layer 22 was grown. Next, a p-type electron confinement layer made of Mg-doped AlGaN, a p-type light guide layer made of undoped GaN, a superlattice layer in which layers made of undoped Al _0.16 Ga _0.84 N and layers made of Mg-doped GaN are alternately laminated A p-type contact layer made of a p-type cladding layer and Mg-doped p-type GaN was grown. Thereby, the p-type semiconductor layer 23 was formed. Thereafter, the wafer was annealed at 700 ° C. in a nitrogen atmosphere to further reduce the resistance of the p-type semiconductor layer 23.

  After the nitride semiconductor layer 20 is stacked in this manner, a part of the p-type semiconductor layer 23, the active layer 22, and the n-type semiconductor layer 21 are sequentially etched using a mask having a desired shape, and an n-type cladding layer is formed. The surface of was exposed. Here, each laser element is formed to have a width of 200 μm.

Thereafter, an SiO ₂ film and a resist film are formed on the uppermost p-type contact layer, and the resist film is patterned into a predetermined shape by photolithography and etching processes, and further, the SiO ₂ film is patterned using the resist film as a mask. did. A stripe-shaped ridge 23 a having a width of about 1.5 μm and a height of about 0.5 μm was formed in the p-type semiconductor layer 23 using the mask thus obtained.

Subsequently, a ZrO ₂ film is formed as a first insulating film 41 in a stripe pattern with a thickness of 4000 mm on the surface of the p-type semiconductor layer 23 by the ECR sputtering method while leaving the mask made of the previously formed SiO ₂ film. did. At this time, the distance between the side surface of the ridge 23a and the side surface of the first insulating film 41 was 10 μm (see FIG. 2A).

Subsequently, a ZrO ₂ film having a thickness of 2000 mm was formed as the second insulating film 42 on the surface of the first insulating film 41 and the ridge 23a and the side surface of the ridge 23a of the p-type semiconductor layer 23 by ECR sputtering. Thereafter, the mask on the ridge 23a and the second insulating film 42 on the mask were removed by lift-off to form the second insulating film 42 (see FIG. 2B).

  Next, a p-electrode 50 was formed on the ridge 23a and the second insulating film 42 by using magnetron sputtering. In the p-electrode 50, the p-electrode first layer 51 is formed of platinum (Pt) having a thickness of 300 mm, and the p-electrode second layer 52 is formed of gold (Au) having a thickness of 5000 mm (see FIG. 2C and (See FIG. 3 (a)).

After forming the p-electrode 50, annealing was performed at 700 ° C. or lower in an atmosphere containing oxygen and nitrogen.
Then, the back surface of the GaN substrate was polished, and an n-electrode 60 was formed on the polished surface. The n-electrode 60 was formed from the substrate 10 side in the order of vanadium (V) having a thickness of 100 mm, platinum (Pt) having a thickness of 2000 mm, and gold (Au) having a thickness of 3000 mm.

Thereafter, the semiconductor laser is divided from a wafer shape into a bar shape. At this time, the resonator length of the laser element is 600 μm. The semiconductor laser divided into bar shapes was sandwiched by spacers from above and below, and an end face protective film was formed on the resonator end face. This end face protective film was formed of Al ₂ O ₃ with a thickness of 1200 mm on the emission side and 6.5 pairs of Al ₂ O ₃ / ZrO ₂ on the reflection side. The end face protective film is formed from the resonator end face to the surface of the semiconductor layer, and the end face of the electrode is covered with the end face protective film on the upper surface of the semiconductor laser element. A second region having a narrow width of the end face protective film is provided on the upper surface of the semiconductor laser element, and has a notch at the end opposite to the end face of the resonator. Note that the previously formed electrode is exposed at the notch. The notches are provided on both sides of the element, and the size of the upper surface of the semiconductor laser element is 10 μm in the length in the resonator direction (the length of the second region 100b), and the length in the width direction of the laser element. Is 20 μm. Further, the length from the resonator end face of the end face protective film to the end of the end face protective film on the upper surface of the semiconductor laser element is 30 μm immediately above the ridge and at the periphery of the ridge, and the length at the periphery of the element (that is, the first region) The length of 100a is about 20 μm. Further, the film thickness of the end face protective film on the surface of the semiconductor laser element is formed to be about 700 mm at the ridge immediately above and around the ridge, and about 400 mm at the periphery of the element (FIGS. 2D and 3 ( b) and (b) ′, see FIG.
And it cleaved from bar shape to chip shape. As a result, a semiconductor laser element having a resonator length of 200 μm and a chip width of 600 μm is obtained. The semiconductor laser element was manufactured by connecting the wire 70 on the element peripheral part 50c of the chip-shaped semiconductor laser element.
In the semiconductor laser device obtained as described above, since the end face protective film covers the end portion of the electrode, peeling of the electrode can be suppressed, and the end face protective film does not reach the wire bonding portion on the element peripheral edge portion 50c. Therefore, peeling of the wire connected to the electrode on the ridge can be prevented, and a semiconductor laser element with stable vertical and horizontal optical confinement can be obtained.

(Example 2)
It is formed in the same manner as in Example 1 until the surface of the n-clad layer is exposed.
Subsequently, using the mask formed on the uppermost p-type contact layer, the ridge 23a and the protrusion 23b are formed. The ridge 23a has a width of 1.5 μm, and the convex portion 23b is formed with a width of 80 μm at a position 10 μm away from the side surface of the ridge 23a. Both heights are about 0.5 μm.

Subsequently, a ZrO ₂ film having a thickness of 2000 mm is formed on the side surface of the ridge 23a and the surface other than the upper surface of the ridge 23a of the p-type semiconductor layer 23 by ECR sputtering. Thereafter, the mask on the ridge 23a and the insulating film 40 on the mask are removed by lift-off to form the insulating film 40 in a pattern.

Thereafter, it can be formed in the same manner as in Example 1.
In the semiconductor laser device obtained as described above, since the end face protective film covers the end portion of the electrode as in Example 1, it is possible to suppress the peeling of the electrode, and the wire bonding portion on the device peripheral portion 50c Since the end face protective film does not go around, peeling of the wire connected to the electrode on the ridge can be prevented.

(Example 3)
The same procedure as in Example 1 is performed except that the ridge 23a is formed with a width of 7.0 μm. The semiconductor laser device obtained as described above exhibits the effect of preventing the peeling of the wire in substantially the same manner as in the first embodiment.

Example 4
The semiconductor laser device is formed in the same manner as in Example 1 except that the resonator length is 400 μm. As a result, the length of the wire-bondable region is reduced as compared with the other embodiments, but the end face protective film does not come into contact with the wire bonding portion on the element peripheral portion 50c. Similarly to the above, peeling of the wire connected to the electrode on the ridge can be prevented.

(Example 5)
The semiconductor laser element is formed in the same manner as in Example 1 except that the width is 150 μm. As a result, the width of the first insulating film is narrowed, and the width of the p-electrode formed thereon is also narrowed. Therefore, the width of the region capable of wire bonding at the periphery of the element is smaller than that of the other embodiments. However, since the end face protective film does not go around the wire bonding portion on the element peripheral edge portion 50c, it is possible to prevent the wires connected to the electrodes on the ridge from being peeled off as in the other embodiments.

  The semiconductor laser device according to the present invention includes all devices to which the laser device can be applied, such as a CD player, an MD player, various game machines, a DVD player, a trunk line / optical communication system such as a telephone line and a submarine cable, Medical equipment such as laser scalpel, laser therapy machine, laser acupressure machine, printing machine such as laser beam printer, display, various measuring devices, laser level, laser measuring machine, laser speed gun, optical sensing equipment such as laser temperature system, It can be used in various fields such as laser power transportation.

It is sectional drawing which shows typically the structure of the semiconductor laser element which concerns on embodiment of this invention. FIG. 3 is a cross-sectional view schematically showing a manufacturing process of the semiconductor laser element shown in FIG. It is a top view which shows typically the structure and manufacturing process of the semiconductor laser element which concern on embodiment of this invention. It is an enlarged view near the cavity end face of the semiconductor laser device according to the embodiment of the present invention. (Α) It is an enlarged view showing a cross section immediately above the ridge. (Β) It is an enlarged view showing a cross section around the ridge. (Γ) is an enlarged view showing a cross section at the periphery of the element. It is sectional drawing which shows typically the structure of the semiconductor laser element which concerns on another embodiment of this invention. It is sectional drawing which shows the structure of the conventional semiconductor laser element typically.

Explanation of symbols

10 substrate 20 nitride semiconductor layer 21 n-type semiconductor layer (first conductivity type semiconductor layer)
22 active layer 23 p-type semiconductor layer (second conductivity type semiconductor layer)
23a Ridge 23b Protruding part 40 Insulating film 41 First insulating film 42 Second insulating film 50 P electrode 50a Immediately above ridge 50b Ridge peripheral part 50c Element peripheral part 60 N electrode 70 Wire 80, 90 Spacer 100 End face protective film 100a First region 100b 2nd area 101 Notch part, electrode exposure part

Claims (10)

A stacked semiconductor including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, a striped ridge formed in the stacked semiconductor, an electrode formed on the ridge, and formed in the stacked semiconductor A semiconductor laser device having a cavity end face,
Having an end face protective film covering the top surface of the laminated semiconductor and the electrode continuously from the resonator end face;
2. A semiconductor laser device according to claim 1, wherein the end face protective film has a notch at the end opposite to the resonator end surface on the upper surface of the semiconductor laser device.
A stacked semiconductor including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, a striped ridge formed in the stacked semiconductor, an electrode formed on the ridge, and formed in the stacked semiconductor A semiconductor laser device having a cavity end face,
Having an end face protective film covering the top surface of the laminated semiconductor and the electrode continuously from the resonator end face;
The end surface protective film has a first region and a second region in order from the resonator end surface side on the upper surface of the semiconductor laser element, and the end surface protective film of the second region is an end surface protective film of the first region. A semiconductor laser device characterized in that the lateral width is narrower than that.
An insulating film is formed on a surface of the laminated semiconductor, the electrode is formed from the ridge to the insulating film, and an upper surface of the electrode is higher than an upper surface of the insulating film. The semiconductor laser device according to claim 1 or 2.
The insulating film has at least a first insulating film and a second insulating film,
The first insulating film covers the surface of the stacked semiconductor separated from the ridge by a predetermined distance, and the second insulating film includes a side surface of the ridge, the surface of the stacked semiconductor exposed between the ridge and the first insulating film, and 4. The semiconductor laser device according to claim 3, wherein the first insulating film is covered.
The peripheral portion of the ridge directly covering the surface of the laminated semiconductor where the second insulating film is exposed between the ridge and the first insulating film, and the second insulating film covers the surface of the laminated semiconductor via the first insulating film. An element peripheral portion,
5. The semiconductor laser device according to claim 4, wherein the upper surface of the electrode is formed such that the upper surface immediately above the ridge is higher than the upper surface of the peripheral portion of the ridge, and the upper surface of the periphery of the device is higher than the upper surface of the ridge.
The semiconductor laser device according to claim 5, wherein the cutout portion is provided on the peripheral portion of the device.
6. The semiconductor laser device according to claim 5, wherein the second region has an end face protective film portion and an electrode exposed portion, and the end face protective film portion is formed immediately above the ridge and in the periphery of the ridge.
8. The length of the end face protective film from the resonator end face to the opposite end is formed so that the portion immediately above the ridge and the peripheral portion of the ridge are longer than the peripheral portion of the element. The semiconductor laser device according to any one of the above.
9. The semiconductor laser device according to claim 5, wherein a thickness of the end face protective film is formed so that a portion immediately above the ridge and a peripheral portion of the ridge are thicker than a peripheral portion of the device.
  10. The semiconductor laser device according to claim 4, wherein the first insulating film insulating film and the second insulating film insulating film are made of the same material. 11.

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