TW201349569A - Light-emitting component and method for manufacturing the same - Google Patents

Abstract

A light-emitting component includes a first type doped semiconductor layer, a light-emitting layer, a second type doped semiconductor layer, a contact layer and an electrode unit. The light-emitting layer is disposed on the first type doped semiconductor layer and converts received electrical energy into light; the second type doped semiconductor layer is disposed on the light-emitting layer and has an electrical polarity opposite to that of the first type doped semiconductor layer; the contact layer is made of semiconductor material and has an orthorhombic lattice system. The contact layer is disposed on the second type doped semiconductor layer. The electrode unit transmits external electrical energy to the light-emitting layer. This invention uses the contact layer to reduce the contact resistance with the electrode unit and at the same time reduces the working voltage and increases the overall electrical conductivity of the elements, thereby increasing the overall light emission efficiency of the elements. This invention also provides a method for manufacturing a light-emitting component.

Description

Light-emitting element and manufacturing method thereof

The present invention relates to a light-emitting element and a method of fabricating the same, and more particularly to a light-emitting element including a contact layer and a method of fabricating the same.

Referring to FIG. 1, the current light-emitting element comprises a first type doped semiconductor layer 11, a light-emitting layer 12, a second-type doped semiconductor layer 13, and an electrode unit 14 made of a conductive material.

The first type doped semiconductor layer 11 is made of an n-type semiconductor material, such as n-type gallium nitride, so it is generally called an n-type doped semiconductor layer (hereinafter, the first type doped semiconductor layer 11 is referred to as n-type doping). Semiconductor layer). The second type doped semiconductor layer 13 is made of a p-type semiconductor material, such as p-type gallium nitride, so it is generally called a p-type doped semiconductor layer (hereinafter, the second type doped semiconductor layer 13 is referred to as p-type doping). Semiconductor layer). The light-emitting layer 12 is interposed between the n-type doped semiconductor layer and the p-type doped semiconductor layer, and converts electrical energy into light energy to emit light when receiving electrical energy.

The electrode unit 14 is made of a conductive material such as a metal element or a metal alloy, and includes a first electrode 141 disposed on the n-type doped semiconductor layer, and a second disposed on the p-type doped semiconductor layer. The electrode 142, the first and second electrodes 141, 142 can transmit electrical energy from the outside.

When the first and second electrodes 141, 142 of the electrode unit 14 receive electrical energy from the outside, electrical energy passes through the n-type doped semiconductor layer and the p-type doped semiconductor layer to reach the luminescent layer 12, and electrical energy is generated in the luminescent layer 12. Photoelectric reaction and luminescence.

Since the current needs to flow through the p-type doped semiconductor layer to reach the light-emitting layer 12, but the p-type doped semiconductor layer is a semiconductor material, the rate of current flow and the conductivity are not as the electrode unit 14 composed of a conductor material. The speed is high, and the contact resistance between the second electrode 142 and the p-type doped semiconductor layer is high, so that the operating voltage of the entire light-emitting element is high, and the luminous efficiency is not ideal.

Although a transparent, highly conductive metal oxide such as Indium Tin Oxide (ITO) is found, the metal oxide as a transparent conductive layer is then introduced into the above-described technique of the light-emitting element. To reduce the contact resistance between the p-doped semiconductor layer and the second electrode 142, and at the same time increase the lateral spread uniformity of the current. However, there is a problem that the difference in material type between the transparent conductive layer made of indium tin oxide and the p-type doped semiconductor layer is too large, resulting in too high contact resistance.

Accordingly, it is an object of the present invention to provide a light-emitting element having a low contact resistance.

Thus, the light-emitting element of the present invention comprises a first type doped semiconductor layer, a light emitting layer, a second type doped semiconductor layer, a contact layer, and an electrode unit.

The luminescent layer is disposed on the first type doped semiconductor layer and converts electrical energy into light when receiving electrical energy, and the second type doped semiconductor layer is disposed on the luminescent layer and is formed with the first type doped semiconductor layer In the opposite polarity, the contact layer is disposed on the second type doped semiconductor layer, the contact layer is composed of a semiconductor material, and the lattice system of the contact layer is orthorhombic (orthormbic System), the electrode unit transmits electrical energy from the outside to the luminescent layer.

Further, another object of the present invention is to provide a method of fabricating a light-emitting element having a low contact resistance.

Therefore, the method for fabricating the light-emitting device of the present invention comprises an epitaxial step and an electrode setting step.

The epitaxial step sequentially forms a hexagonal first-type doped semiconductor layer, a hexagonal-based luminescent layer, and a hexagonal system on a substrate by means of an organometallic chemical vapor deposition method. The second type doped semiconductor layer and an orthorhombic contact layer.

The electrode setting step forms an electrode unit that can transfer electrical energy from the outside to the luminescent layer.

The invention has the effect of forming a contact layer with low contact resistance on the second type doped semiconductor layer by an organometallic chemical vapor deposition method, thereby reducing the operating voltage of the element and thereby improving the luminous efficiency of the element.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Before the present invention is described in detail, it is noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to FIG. 2, a preferred embodiment of the light-emitting device of the present invention comprises a substrate 20, a first type doped semiconductor layer 21, a second type doped semiconductor layer 23, and a clip formed on the substrate 20. a light-emitting layer 22 disposed between the first-type doped semiconductor layer 21 and the second-type doped semiconductor layer 23 is formed in the first The contact layer 24 on the doped semiconductor layer 23, and an electrode unit 25 that transfers electrical energy from the outside to the luminescent layer 22.

The first type doped semiconductor layer 21 is formed on the substrate 20 by an organometallic chemical vapor deposition method and is formed of an n-type nitride semiconductor material. In the first preferred embodiment, the n-type nitride is formed. The semiconductor material is n-type gallium nitride (GaN). The first type doped semiconductor layer 21 is generally referred to as an n-type doped semiconductor layer 21 by researchers in the field, and thus the first type doped semiconductor layer 21 is hereinafter referred to as an n-type doped semiconductor layer.

The light emitting layer 22 is formed on the n-type doped semiconductor layer 21 and converts electrical energy into light energy when receiving electrical energy. In particular, the light-emitting layer 22 may be a double hetero-junction structure, a single quantum well structure, or a multiple quantum well structure, wherein multiple quantum well structures The well structure may include a plurality of barrier layers and a plurality of well layers, the barrier layers and the well layers being sequentially staggered from the surface of the n-type doped semiconductor layer, wherein the barrier layers are sequentially staggered The part is gallium nitride (GaN), and the well layers are indium gallium nitride (InGaN). The arrangement between the well portion and the barrier layer portion of the luminescent layer 22 is well known to those skilled in the art and will not be further described herein.

The second type doped semiconductor layer 23 is formed on the light emitting layer 22, and is formed on the surface of the light emitting layer 22 away from the n-type doped semiconductor layer 21 by organometallic chemical vapor deposition, and is a p-type nitride. A semiconductor material is constructed. In the first preferred embodiment, the p-type nitride semiconductor material is p-type gallium nitride. The second type doped semiconductor layer 23 is usually used by researchers in the field. Referring to the p-type doped semiconductor layer, the second-type doped semiconductor layer 23 is hereinafter referred to as a p-type doped semiconductor layer 23.

It is to be noted that the n-type doped semiconductor layer 21, the light-emitting layer 22 and the p-type doped semiconductor layer 23 are all composed of GaN based and n-type doped. The semiconductor layer 21, the light-emitting layer 22, and the p-type doped semiconductor layer 23 are all solid forms of a single crystal, and their lattice systems are all hexagonal systems.

The contact layer 24 is transparent and electrically conductive, and is formed in the p-type doped semiconductor layer 23 away from the surface of the n-type doped semiconductor layer 21 by organometallic chemical vapor deposition. The contact layer 24 includes a majority from the p An island-like structure 241 from which the surface of the doped semiconductor layer 23 protrudes.

The contact layer 24 is made of a semiconductor material, the contact layer 24 is a solid form of a single crystal, and the lattice system is an orthorhombic system, and the composition of the contact layer 24 can be In _y Ga _1-y O _x N _{1- x} , where 0 < y < 1, 0 < x ≦ 1. When x=1, the composition of the contact layer 24 is In _y Ga _1-y O, where 0 < y < 1.

Referring to FIG. 3 and FIG. 4, the two figures are respectively a component analysis diagram of the contact layer 24 which is actually measured according to a specific example of the preferred embodiment. The chemical composition of the contact layer 24 is analyzed by an energy analyzer (EDS) whose design is JEOL and model JSM-6700F (Fig. 3), and then the peak of each chemical component is used to calculate the peak as shown in Fig. 4. Show the weight percentage of each component.

It can be clearly seen from the drawing that the contact layer 24 is composed of at least three elements of indium, gallium and oxygen, and after calculation, the weight percentage of each element is about 77.97 wt% of indium and 16.36 wt% of gallium. The oxygen contained 5.67 wt%.

Both the contact layer 24 of the present invention and the p-type doped semiconductor layer 23 are in a single crystal solid form, so that the material compatibility between the two is high. Therefore, the adhesion between the contact layer 24 and the p-type doped semiconductor layer 23 is good.

Moreover, since the contact layer 24 is made of an electrically conductive material, current flows through the contact layer relatively smoothly, and has better conductivity. In the preferred embodiment, the structure of the contact layer 24 is found to be an orthorhombic system by an electron microscope, and the atomic bonding mode is regularly arranged, and the power supply hole is more easily traversed, thereby providing excellent conductivity.

Moreover, since the contact layer 24 includes a plurality of island structures 241, the island structure 241 of the contact layer 24 can increase the efficiency of current transfer in the vertical direction, and preferably, the organometallic chemical vapor deposition method is suitable for forming a size smaller than 300 nm. Or a low-density island structure, and an island structure larger than 30 nm can more effectively increase the efficiency of current transfer in the vertical direction. Therefore, preferably, each of the island structures 241 has an average diameter of 30 nm to 300 nm, an average height of each of the island structures 241 is 10 nm to 20 nm, and a pitch of two adjacent island structures 241 is greater than 100 nm.

The electrode unit 25 includes a first electrode 251 electrically connected to the n-type doped semiconductor layer 21 and on the same surface as the light-emitting layer 22, and a second electrode 252 electrically connected to the contact layer 24. Lateral type of light-emitting element.

When the first and second electrodes 251, 252 cooperate to transmit electrical energy from the outside, the electrical energy is transmitted to the luminescent layer 22 via the contact layer 24, the n, p-type doped semiconductor layers 21, 23 to convert electrical energy into light. It can emit light, and because the conductivity of the contact layer 24 is good, the current is also quickly reached to the light-emitting layer 22 Further increasing the probability that the electron holes will combine to generate light, thereby effectively improving the internal quantum efficiency of the element.

In particular, the light-emitting element of the present invention can be packaged in a flip-chip manner, except that it can be applied to a general package.

Referring to FIG. 5, it should be noted that the contact layer 24 of the preferred embodiment of the present invention described above may further include a layer body 242 formed on the p-type doped semiconductor layer 23 as shown in FIG. The layer body 242 of the contact layer 24 not only provides good ohmic contact with the p-type doped semiconductor layer 23, but also has good adhesion to the p-type doped semiconductor layer 23, thereby greatly increasing lateral diffusion of current. The degree of uniformity. Or as shown in FIG. 6, the contact layer 24 further includes an island structure 241 extending from the layer body 242 away from the p-type doped semiconductor layer 23 at a plurality of intervals, that is, the contact layer 24 includes a layer. The body 242, and most of the island-like structure 241 formed from the surface of the layer body 242, thereby achieving uniform lateral current diffusion, and also has a characteristic of high current transfer efficiency in the vertical direction.

Referring to FIG. 7, it should be noted that the present invention may further include a transparent conductive layer 26 covering the contact layer 24. Here, the light-emitting element illustrated in FIG. 6 is further provided with a transparent conductive layer 26, which is described. The two electrodes 252 are connected to the transparent conductive layer 26, and the contact layer 24 is electrically connected to the electrode unit 25 through the transparent conductive layer 26. The current supplied to the electrode unit 25 is more uniformly transmitted to the light-emitting layer 22 by the transparent conductive layer 26 in cooperation with the contact layer 24.

The transparent conductive layer 26 is composed of a metal oxide or a metal film as a main material, wherein the metal oxide may be selected from indium tin (indium tin) Oxide, ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), zinc oxide, aluminum tin oxide (ATO), Aluminum zinc oxide (AZO), cadmium indium oxide (CIO), cadmium zinc oxide (CZO), gallium zinc oxide (GZO), and tin oxyfluoride (FTO) And one of the combinations is composed of materials; and the metal film can be composed of nickel (Ni), gold (Au) and one of them as a material. Preferably, the transparent conductive layer 26 is selected from the group consisting of indium tin oxide, aluminum-doped zinc oxide, indium zinc oxide, and combinations thereof.

It should be noted here that the lattice system of the transparent conductive layer 26 is a cubic system; and the transparent conductive layer 26 is a polycrystalline or amorphous solid form.

In the preferred embodiment of the present invention, the transparent conductive layer 26 is exemplified by indium tin oxide (ITO), but is not limited thereto.

Further, it is worth mentioning that the contact layer 24 of the present invention can also be applied to a vertical type of light-emitting element. Referring to FIG. 8, when the first electrode 251 of the electrode unit 25 is disposed under the n-type doped semiconductor layer 21 (ie, the side away from the light-emitting layer 22), that is, a vertical-type light-emitting element is formed. The simple change of the light-emitting element shown in Fig. 7 is a vertical light-emitting element.

The preferred embodiment of the above-described light-emitting device of the present invention can be more clearly understood by the following description of the production method.

Referring to FIG. 2 and FIG. 9, a manufacturing method of a preferred embodiment of the light-emitting device of the present invention comprises an epitaxial step 31 and an electrode setting step 32.

First, the epitaxial step 31 is performed to perform organic metal chemical vapor deposition A first hexagonal doped semiconductor layer 21, a light emitting layer 22, and a second doped semiconductor layer 23, and an orthorhombic contact layer 24 are formed on the substrate 20 in sequence. .

The first type doped semiconductor layer 21, the light emitting layer 22, and the second type doped semiconductor layer 23 in the epitaxial step 31 are composed of a gallium nitride group as a main material. And the chemical formula In _y Ga _1-y O _x N _1-x of the contact layer 24 in the epitaxial step 31, wherein 0 < y < 1, 0 < x ≦ 1. The first type doped semiconductor layer 21, the light emitting layer 22, the second type doped semiconductor layer 23, and the contact layer 24 described above are all in the form of a single crystal.

The contact layer 24 in the epitaxial step 31 is formed by introducing trimethylgallium ((CH ₃ ) ₃ Ga, or Trimmethyl Ga, or TMGa for short) as a gallium source in the cavity of the organometallic chemical vapor deposition reactor. , trimethyl indium as a source of indium ((CH ₃ ) ₃ In, or Trimmethyl In, TMIn for short), an oxide as an oxygen source, and nitrogen (N ₂ ) as a carrier, followed by an organometallic chemical gas Made by phase deposition. The oxide is selected from the group consisting of H ₂ O, O ₂ , CO ₂ , CO, and a combination thereof.

It should be noted that the contact layer 24 can form the island structures 241 spaced apart from each other by controlling the temperature in the cavity, the flow rate of the airflow, or the time of deposition according to a desired pattern. The layer body 242, and the average diameter of each of the island structures 241 obtained by the manufacturing method of the preferred embodiment is 30 nm to 300 nm, and the average height of each of the island structures 241 is 10 nm to 20 nm. The spacing between two adjacent island structures 241 is greater than 100 nm.

Then, the electrode setting step 32 is performed to form the first and the first The two doped semiconductor layers 21, 23 are electrically connected to transmit electric energy from the outside to the electrode unit 25 of the light emitting layer.

In more detail, the electrode setting step 32 is to form the first electrode 251 and the second electrode 252 on the first type doped semiconductor layer 21 and the second type doped semiconductor layer 23, respectively. The electrode unit 25 is formed by the second electrode 252 together with the second electrode 252.

The above-described production method utilizes the type of the oxide-containing gas in the organometallic chemical vapor deposition reactor and the flow rate during the reaction, and further combines TMGa as a gallium source, TMIn as an indium source, and a cavity. The temperature and pressure in the body, and the top surface of the second type doped semiconductor layer 23 constitutes a contact layer 24 which is transparent and permeable and excellent in conductivity, thereby overcoming the current indium tin oxide and the second type doped semiconductor layer 23 Poor adhesion and high contact resistance.

Referring to FIG. 10 and FIG. 7, the manufacturing method of another preferred embodiment of the light-emitting device of the present invention may further comprise a transparent conductive layer forming step 33 performed before the electrode setting step 32, by using physical vapor deposition. A transparent conductive layer 26 made of a metal oxide or a metal thin film as a main material is formed on the surface of the contact layer 24, and a light-emitting element as shown in FIG. 7 can be fabricated. The second-type doped semiconductor layer 24 and the A light-emitting element having the contact layer 24 and the transparent conductive layer 26 is formed between the second electrodes 252.

The manufacturing method of the preferred embodiment has good adhesion by the transparent contact layer 24 and the second type doped semiconductor layer 23, and the lattice system of the contact layer 24 has an orthorhombic system and has good conductivity. Cooperating with the transparent conductive layer 26 to laterally diffuse the current to achieve a more uniform current distribution, so that the light-emitting element The internal quantum efficiency is effectively increased, which in turn significantly improves the overall luminous efficiency of the component.

In summary, the orthorhombic contact layer 24 of the present invention is disposed between the p-type doped semiconductor layer 23 and the electrode unit 25, and has better conductivity, and the transparent conductive layer 26 is directly disposed at present. The contact resistance between the p-type doped semiconductor layer 23 and the electrode unit 25 is low, and the problem of poor adhesion between the transparent conductive layer 26 and the p-type doped semiconductor layer 23 and a low rate of hole rate is overcome, thereby increasing the internal The quantum efficiency and the overall luminance of the light can indeed achieve the object of the present invention.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

20‧‧‧Substrate

21‧‧‧First type doped semiconductor layer

22‧‧‧Lighting layer

23‧‧‧Second type doped semiconductor layer

24‧‧‧Contact layer

241‧‧‧ island structure

242‧‧‧ layer

25‧‧‧Electrode unit

251‧‧‧First electrode

252‧‧‧second electrode

26‧‧‧Transparent conductive layer

31‧‧‧ Epitaxial steps

32‧‧‧Electrode setting steps

33‧‧‧Transparent conductive layer formation step

1 is a cross-sectional view showing a conventional light-emitting element; FIG. 2 is a cross-sectional view showing a preferred embodiment of the present invention; and FIG. 3 is a compositional analysis diagram illustrating a contact layer of the preferred embodiment Including indium, gallium, and oxygen; FIG. 4 is a content analysis table indicating that the contact layer contains indium, gallium, and oxygen; FIG. 5 is a schematic cross-sectional view showing that the contact layer of the present invention includes a layer; FIG. A schematic cross-sectional view showing that the contact layer of the present invention comprises a layer body and an island structure; 7 is a schematic cross-sectional view showing a transparent conductive layer of the present invention; FIG. 8 is a schematic cross-sectional view showing the vertical light-emitting element of the present invention; FIG. 9 is a flow chart illustrating a method for fabricating the light-emitting element of the present invention. And FIG. 10 is a flow chart illustrating that the method of fabricating the light-emitting device of the present invention further includes a transparent conductive layer forming step.

20‧‧‧Substrate

21‧‧‧First type doped semiconductor layer

22‧‧‧Lighting layer

23‧‧‧Second type doped semiconductor layer

24‧‧‧Contact layer

241‧‧‧ island structure

25‧‧‧Electrode unit

251‧‧‧First electrode

252‧‧‧second electrode

Claims (19)

A light emitting device comprising: a first type doped semiconductor layer; a light emitting layer disposed on the first type doped semiconductor layer and converting electrical energy into light when receiving electrical energy; and a second type doped semiconductor layer, Provided on the light-emitting layer and opposite to the first type doped semiconductor layer; a contact layer formed of a semiconductor material and disposed on the second type doped semiconductor layer, and a lattice of the contact layer The system is an orthorhombic system; and an electrode unit that transfers electrical energy from the outside to the luminescent layer. The light-emitting element according to claim 1, wherein the first-type doped semiconductor layer, the light-emitting layer, and the second-type doped semiconductor layer are composed of a gallium nitride-based material. The light-emitting element according to claim 1, wherein the lattice system of the first-type doped semiconductor layer, the light-emitting layer, and the second-type doped semiconductor layer is a hexagonal system. The light-emitting element according to claim 1, wherein the first-type doped semiconductor layer, the light-emitting layer, the second-type doped semiconductor layer, and the contact layer are in the form of a single crystal. The light-emitting element according to the first aspect of the invention, wherein the contact layer comprises an island structure in which a plurality of the doped semiconductor layers are protruded upward. A light-emitting element according to claim 1, wherein the contact The layer includes a layer body formed on the second type doped semiconductor layer. The light-emitting element according to claim 6, wherein the contact layer further comprises an island-like structure extending from the layer body in a direction away from the second-type doped semiconductor layer. The light-emitting element according to claim 5, wherein the island-shaped structure has an average diameter of 30 nm to 300 nm and an average height of 10 nm to 20 nm. The light-emitting element according to claim 5, wherein the distance between two adjacent island-like structures is greater than 100 nm. The light-emitting element according to claim 1, wherein the contact layer has a chemical formula of In _y Ga _1-y O _x N _1-x , wherein 0 < y < 1, 0 < x ≦ 1. The light-emitting element according to claim 1, further comprising a transparent conductive layer covering the contact layer. The light-emitting element according to claim 11, wherein the transparent conductive layer is selected from the group consisting of indium tin oxide, aluminum-doped zinc oxide, indium zinc oxide, and a combination thereof. The light-emitting element according to claim 11, wherein the lattice system of the transparent conductive layer is a cubic system. The light-emitting element according to claim 11, wherein the transparent conductive layer is in a polycrystalline or amorphous solid form. A method for fabricating a light-emitting device, comprising: an epitaxial step of sequentially forming a hexagonal first-type doped semiconductor layer on a substrate by means of an organometallic chemical vapor deposition method; a hexagonal light emitting layer, a hexagonal second type doped semiconductor layer, and an orthorhombic contact layer; and an electrode setting step to form an electrical energy that can be transmitted from the outside to the light The electrode unit of the layer. The method for fabricating a light-emitting device according to claim 15, wherein the chemical formula of the contact layer is In _y Ga _1-y O _x N _1-x , wherein 0 < y < 1, 0 < x ≦ 1 . The method for producing a light-emitting device according to claim 16, wherein the epitaxial step introduces trimethylgallium as a gallium source, trimethylindium as an indium source, and an oxide as an oxygen source, and Nitrogen as a carrier grows the contact layer. The method for fabricating a light-emitting device according to claim 17, wherein the oxide in the epitaxial step is selected from the group consisting of H ₂ O, O ₂ , CO ₂ , CO, and a combination thereof. . The method for fabricating a light-emitting device according to claim 15 further comprising a transparent conductive layer forming step of forming a metal oxide or a metal film as a main material on the surface of the contact layer by physical vapor deposition. Transparent conductive layer.