TWI692121B - Light-emitting device and the manufacturing method thereof - Google Patents

Abstract

A light-emitting device comprises a first semiconductor layer; and a transparent conductive oxide layer comprising a diffusion region having a first metal material and a non-diffusion region devoid of the first metal material, wherein the non-diffusion region is closer to the first semiconductor layer than the diffusion region.

Description

Light emitting element and its manufacturing method

The invention relates to a light-emitting element and a method for manufacturing the same, in particular to a light-emitting element having a transparent conductive oxide layer with a diffusion area and a non-diffusion area and a method for manufacturing the same.

A light emitting diode (LED) is a solid-state semiconductor device. The structure of the light emitting diode (LED) includes a p-type semiconductor layer, an n-type semiconductor layer, and a light-emitting layer, wherein the light-emitting layer is formed on the p-type semiconductor layer and n Type semiconductor layer. The structure of the LED includes compound semiconductors composed of group III-Ⅴ elements, such as gallium phosphide (GaP), gallium arsenide (GaAs), and gallium nitride (GaN). The principle of light emission is to use n under an external electric field. The electrons provided by the p-type semiconductor layer and the holes provided by the p-type semiconductor layer recombine near the pn junction of the light-emitting layer to convert electrical energy into light energy.

A light-emitting device including a first semiconductor layer; and a transparent conductive oxide layer including a diffusion region having a first metal material and a non-diffusion region not having a first metal material, wherein the non-diffusion region is larger than the diffusion region Closer to the first semiconductor layer.

In order to make the above-mentioned features and advantages of the present invention more obvious and understandable, the embodiments are specifically described below in conjunction with the accompanying drawings for detailed description as follows. In the drawings or descriptions, similar or identical parts are given the same reference numerals, and in the drawings, the shape or thickness of the elements may be enlarged or reduced. It should be noted that the elements not shown or described in the figure may be in a form known to those skilled in the art.

1A-1C are a method of manufacturing a light-emitting device 1 according to a first embodiment of the present invention. The manufacturing method includes the following steps:

The first step:

A substrate 10 is provided, such as a sapphire substrate. A semiconductor stack 20 includes a first semiconductor layer 13 having a first polarity, a second semiconductor layer 11 having a second polarity, and an active layer 12 formed on the substrate 10. The active layer 12 has a structure, such as a multiple quantum well (MQW) structure mainly composed of indium gallium nitrogen, formed between the first semiconductor layer 13 and the second semiconductor layer 11.

In an example of this embodiment, the first semiconductor layer 13 may be an n-type gallium nitride (GaN) layer, and the second semiconductor layer 11 may be a p-type gallium nitride (GaN) layer.

The first semiconductor layer 13 and the second semiconductor are formed by an epitaxial method, such as organic metal chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or hydride vapor deposition (HVPE) Layer 11, or active layer 12.

The second step:

In the second step, a transparent conductive oxide layer 14 is formed on the semiconductor stack 20.

Next, after the transparent conductive oxide layer 14 is formed on the semiconductor stack 20, a metal layer 15 is formed on an upper surface S1 of the transparent conductive oxide layer 14.

The metal layer 15 includes a first metal material including an element selected from the group consisting of Group IIA and Group IIIA. The metal layer 15 can be deposited by vapor deposition at a temperature close to room temperature and a pressure between 1×10-5 Torr and 1×10-7 Torr, preferably close to 2.9×10-6 Under the cavity environment of Torr, it is formed with a predetermined thickness, for example, less than 500 Angstroms (Å).

The transparent conductive oxide layer 14 includes a second metal material including one or more elements selected from the group consisting of transition metals, group IIIA and group IVA, such as indium tin oxide (ITO). The transparent conductive oxide layer 14 can be deposited by vapor deposition at a temperature close to room temperature, with a nitrogen atmosphere and pressure between 1×10-4 Torr and 1×10-2 Torr, preferably close to Under the cavity environment of 5×10-3 Torr, it is formed with a predetermined thickness, for example, less than 3000 Angstroms (Å).

The first metal material of the metal layer 15 is different from the second metal material of the transparent conductive oxide layer 14. In an example of this embodiment, the first metal material includes aluminum (Al), niobium (Nb), tantalum (Ta), yttrium (Y), or a combination thereof. The second metal material includes indium (In) or tin (Sn). The first metal material is easier to react with oxygen than the second metal material.

The third step:

At a temperature between 200°C and 700°C, preferably between 500°C and 600°C, in a substantially oxygen-free environment, such as a nitrogen environment, heat-treating the transparent conductive oxide layer 14 and the metal layer 15 to make the metal layer 15 The first metal material in the diffusion into the transparent conductive oxide layer 14 to form a diffusion region 151, as shown in FIG. 1B, wherein the transparent conductive oxide layer 14 includes a diffusion region 151 with a first metal material and a substantially no A non-diffusion region 141 of metal material, as shown in FIG. 1B. Specifically, the division of the diffusion region 151 and the non-diffusion region 141 can be defined by element analysis. For example, “the non-diffusion region 141 substantially without the first metal material” can refer to the The concentration of the first metal material is lower than the limit of the signal of the first metal element measured by the energy of the OJ electronic spectrometer. The first metal material can react with the oxygen in the transparent conductive oxide layer 14 to form a metal oxide, such as tantalum pentoxide (Ta2O5), aluminum oxide (Al2O3), niobium pentoxide (Nd2O5), yttrium oxide (Y2O3), Or a combination of the above, it can be detected on the transparent conductive oxide layer 14, the upper surface S1 of the transparent conductive oxide layer 14, and/or the interface between the transparent conductive oxide layer 14 and the second semiconductor layer 11. Since the oxygen in the transparent conductive oxide layer 14 is supplied to the first metal material, more metal ions are present in the transparent conductive oxide layer 14, which can improve the conductivity of the transparent conductive oxide layer 14.

The fourth step:

A platform 30 is formed by inductively coupled plasma etching to expose an upper surface S2 of the second semiconductor layer 11, as shown in FIG. 1C.

The fifth step:

A first electrode 61 is formed on the upper surface S2 of the second semiconductor layer 11 and a second electrode 62 is formed on the upper surface S1 of the transparent conductive oxide layer 14 to form a horizontal light-emitting device 1, as shown in FIG. 1C .

The substrate 10 may be an insulating substrate, such as a sapphire substrate. FIG. 1D is a vertical light-emitting device 2 according to another embodiment of the invention. The light-emitting element 2 includes a conductive substrate 21 that includes a conductive material, such as metal or semiconductor. The manufacturing method of the vertical light emitting element 2 includes similar steps as described above, such as the first step to the third step, in which the substrate 10 is replaced with the conductive substrate 21. The step different from the light-emitting element 1 is that a first electrode 63 and a second electrode 62 are formed on opposite sides of the conductive substrate 21.

The materials of the first semiconductor layer 13, the active layer 12, and the second semiconductor layer 11 include an element selected from group III-V semiconductor materials, such as arsenic (As), gallium (Ga), aluminum (Al), and indium (In ), phosphorus (P), or nitrogen (N).

The material of the transparent conductive oxide layer 14 includes a transparent conductive oxide material, such as indium tin oxide (ITO), cadmium tin oxide (CTO), antimony tin oxide, indium zinc oxide, zinc aluminum oxide, zinc oxide, or zinc tin oxide.

According to the first embodiment described in FIGS. 1A-1C, before the heat treatment, the metal layer 15 is a thin layer with a thickness less than 500 Angstroms (Å), and is a discontinuous layer, which has a plurality of metal grains individually distributed in On the transparent conductive oxide layer 14. After the heat treatment, the metal layer 15 completely diffuses into the transparent conductive oxide layer 14 to form the diffusion region 151.

In a variation of the first embodiment shown in FIG. 2, the first metal material of the metal layer 15 is diffused into the transparent conductive oxide layer 14 by heat treatment to form a diffusion region 152, in which the transparent conductive oxide layer 14 includes a diffusion region 152 with a first metal material and a non-diffusion region 142 that does not substantially have a first metal material. A remaining metal layer 153 has a reduced size remaining on the upper surface S1 of the transparent conductive oxide layer 14. The thickness of the remaining metal layer 153 is preferably less than 100 Angstroms (Å), so that the light from the active layer 12 can penetrate. The thickness of the diffusion region 152 is preferably greater than 50 Angstroms (Å).

3A-3C are the second embodiment of the present invention. A metal layer 25 is compared with the metal layer 15 in the first embodiment. The difference between the first embodiment and this embodiment is that the metal layer 25 is a continuous layer with a thickness less than 500 Angstroms (Å). The metal layer 25 The upper surface S1 of the transparent conductive oxide layer 14 is substantially completely covered before the heat treatment. The first metal material of the metal layer 25 is completely diffused into the transparent conductive oxide layer 14 by heat treatment to form a diffusion region 251, wherein the transparent conductive oxide layer 14 includes the diffusion region 251 with the first metal material and a substantially no The non-diffusion region 241 of the first metal material is shown in FIG. 3B. Specifically, the division of the diffusion region 251 and the non-diffusion region 241 can be defined by element analysis. For example, “the non-diffusion region 241 that does not substantially have the first metal material” can refer to the The concentration of the first metal material is lower than the limit of the signal of the first metal element measured by the energy of the Aojie electronic spectrometer. In another example of this embodiment, the first metal material of the metal layer 25 is diffused into the transparent conductive oxide layer 14 by heat treatment to form a diffusion region 252, wherein the transparent conductive oxide layer 14 includes a first metal The material diffusion region 252 and a non-diffusion region 242 that does not substantially have the first metal material, as shown in FIG. 3C. A remaining metal layer 253 has a reduced size remaining on the upper surface S1 of the transparent conductive oxide layer 14. The thickness of the remaining metal layer 253 is preferably less than 100 Angstroms (Å), so that the light from the active layer 12 can penetrate. The thickness of the diffusion region 252 is preferably greater than 50 Angstroms (Å).

Fig. 4 is a third embodiment of the present invention. The difference between the third embodiment and the above embodiments is that an upper surface S3 of the first semiconductor layer 33 is a rough surface, a transparent conductive oxide layer 34 and a metal layer 35 are conformally formed before heat treatment On the first semiconductor layer 33.

Fig. 5 is a fourth embodiment of the present invention. The transparent conductive oxide layer 44 is formed above the semiconductor stack 40, and a substrate 43 is formed below the semiconductor stack 40. The difference between the fourth embodiment and the above embodiments is that the metal layer 45 is formed on the transparent conductive oxide layer 44 in a pattern before heat treatment, and the pattern of the metal layer 45 can be designed to correspond to the electrode of the light emitting element 400 Layout, such as shape or distribution, etc., but the electrode layout of the light emitting element 400 is not limited to that described in this embodiment. The metal layer 45 may include a first metal material including tin (Sn), silver (Ag), nickel (Ni), other metals, or a combination thereof or an alloy thereof. The thickness of the metal layer 45 is less than 50 nanometers (nm). In this embodiment, the thickness of the metal layer 45 may be about 70 Angstroms (Å). In this embodiment, the metal layer 45 may include a grid or mesh pattern. The line width of the grid or mesh pattern of the metal layer is less than 200 nanometers (nm). In this embodiment, the line width is about 100 nanometers (nm). The light emitting device 400 may include a first electrode 402 formed on the transparent conductive oxide layer 44 and a second electrode 404. The first electrode 402 and the second electrode 404 are electrically connected to a first semiconductor layer 13 and a second semiconductor layer 11 as described in the first embodiment and FIG. 1A, respectively. The first electrode 402 includes a first electrode pad 402a and a first extension electrode 402b, and the second electrode 404 includes a second electrode pad 404a and a second extension electrode 404b. The first electrode pad 402a is disposed near a first side 400a of the light emitting element 400, and the second electrode pad 404a is disposed near a second side 400b of the light emitting element 400. The first extension electrode 402b extends from the first electrode pad 402a in a pattern distribution, and defines a first area 401 having an opening 401a and a first area other than the first area 401 on a horizontal plane of the transparent conductive oxide layer 44二区403. The second extension electrode 404b extends from the second electrode pad 404a, and the second electrode pad 404a is located in the first region 401. The density of the 45 grid or mesh pattern of the metal layer is denser in areas with low current density and sparse in areas with high current density. In this embodiment, the grid or mesh pattern density of the metal layer 45 in the second region 403 may be denser than the first region 401. Specifically, the grid pattern corresponding to the metal layer 45 of the first region 401 may be composed of a plurality of blocks 451, each block 451 has a size of 1 μm x 1 μm, corresponding to the metal layer 45 of the second region 403 The grid pattern may be composed of a plurality of blocks 452, and each block 452 has a size of 0.5 μm x 0.5 μm. The pattern density of the plurality of blocks 452 in the second area 403 is greater than that of the plurality of blocks 451 in the first area 401 The pattern density is dense.

In the embodiment of the present invention, the concentration of the first metal material in the diffusion area gradually decreases from the upper surface of the transparent conductive oxide layer to the inside of the transparent conductive oxide layer, or the concentration of the first metal material in the diffusion area moves away from the transparency with a distance The upper surface of the conductive oxide layer gradually decreases. During the heat treatment of the transparent conductive oxide layer and the metal layer, the first metal material in the metal layer, such as aluminum, may react with the oxygen present in the transparent conductive oxide layer to form an oxide of the first metal material, such as oxidation aluminum. An inert environment during the heat treatment process, such as a nitrogen environment, will passivate and protect the transparent conductive oxide layer 14 so that it will not be damaged during subsequent processes, such as inductively coupled plasma etching. In order to prevent the interdiffusion between the first semiconductor layer and the metal layer, thereby damaging the epitaxial quality of the first semiconductor layer, the metal layer is preferably formed opposite the junction of the transparent conductive oxide layer and the first semiconductor layer, To obtain better light-emitting performance, the light-emitting device of the present invention can have a lower forward voltage, a lower sheet resistance, and a higher light extraction efficiency.

The above-mentioned embodiments are used to describe the technical content and features of the invention, so that those skilled in the art can understand and implement the content of the present invention, and it is not intended to limit the scope of the present invention. That is to say, any obvious modifications or changes made by anyone to the present invention do not depart from the spirit and scope of the present invention. For example, the electrical connection method is not limited to series connection. It should be understood that the above-mentioned embodiments of the present invention can be combined or replaced with each other under appropriate circumstances, rather than being limited to the specific embodiments described.

Understandably, for those skilled in the art, different modifications or changes can be applied to the present invention without departing from the spirit and scope of the present invention. The foregoing description is intended to cover the modifications or alterations of the present invention, all of which fall within the patent scope of the present invention and are equal to them.

1, 2, 400 ‧‧‧ light emitting element

10, 43‧‧‧ substrate

20, 40‧‧‧ semiconductor stack

13, 33‧‧‧‧The first semiconductor layer

11‧‧‧Second semiconductor layer

12‧‧‧Active layer

14, 34, 44 ‧‧‧ transparent conductive oxide layer

20‧‧‧ semiconductor stack

15, 25, 35, 45 ‧‧‧ metal layer

S1, S2, S3 ‧‧‧ upper surface

151, 152, 251, 252

141, 142, 241, 242

21‧‧‧Conductive substrate

63、402‧‧‧First electrode

62、404‧‧‧Second electrode

402a‧‧‧First electrode pad

404a‧‧‧Second electrode pad

402b‧‧‧First extended electrode

404b‧‧‧Second extension electrode

400a‧‧‧First side

400b‧‧‧Second side

401‧‧‧The first area

403‧‧‧Second area

153, 253‧‧‧ remaining metal layer

1A-1C are a method of manufacturing a light-emitting device according to an embodiment of the invention.

1D is a cross-sectional view of a light-emitting device according to another embodiment of the invention.

2 is a step of a method for manufacturing a light-emitting device according to an embodiment of the invention.

3A-3C are steps of a method for manufacturing a light-emitting device according to an embodiment of the invention.

4 is an enlarged cross-sectional view of a light-emitting device according to an embodiment of the invention.

5 is a light-emitting device according to an embodiment of the invention.

10‧‧‧ substrate

20‧‧‧ semiconductor stack

11‧‧‧Second semiconductor layer

12‧‧‧Active layer

13‧‧‧First semiconductor layer

14‧‧‧Transparent conductive oxide layer

141‧‧‧Non-proliferation area

151‧‧‧Diffusion area

S1‧‧‧Top surface

Claims (10)

A light-emitting device, comprising: a first semiconductor layer; a second semiconductor layer; an active layer formed between the first semiconductor layer and the second semiconductor layer, wherein the active layer can emit a light; a transparent conductive layer Located on the first semiconductor layer, wherein the transparent conductive layer includes a diffusion region and a non-diffusion region, wherein the non-diffusion region is closer to the first semiconductor layer than the diffusion region, wherein the diffusion region includes a first metal material And a conductive oxide material, the first metal material is distributed in the conductive oxide material, the non-diffusion region includes the conductive oxide material and does not include the first metal material; an electrode is located on the transparent conductive layer; and a metal The layer includes the first metal material between the transparent conductive layer and the electrode, wherein the light from the active layer can penetrate the metal layer, the metal layer includes a thickness less than 100 Angstroms (Å), and the metal The layers contain different thicknesses. The light-emitting element as described in item 1 of the patent application range, wherein the diffusion region includes a thickness greater than 50 Angstroms (Å). The light-emitting element as described in item 1 of the patent application range, wherein the conductive oxide material includes indium tin oxide (ITO), cadmium tin oxide (CTO), antimony tin oxide, indium zinc oxide, zinc aluminum oxide, zinc oxide, or zinc Tin oxide. The light-emitting element as described in item 1 of the patent application range, wherein the concentration of the first metal material in the diffusion region gradually decreases toward the first semiconductor layer. The light-emitting element as described in item 1 of the patent application range, wherein the first metal material includes an element selected from the group consisting of group IIA elements and group IIIA elements. The light-emitting element as described in item 1 of the patent application range, wherein the metal layer includes a plurality of discontinuous layers separated from each other to expose the transparent conductive layer. The light-emitting element as described in item 1 of the patent application range, wherein the conductive oxide material includes a second metal material different from the first metal material. The light-emitting element according to item 1 of the patent application range, wherein the electrode has a layout or a shape, and is electrically connected to the first semiconductor layer and the second semiconductor layer. The light-emitting element as recited in item 8 of the patent application range, wherein the metal layer includes a pattern corresponding to the layout or the shape of the electrode. The light-emitting element as described in item 1 of the patent application range, wherein a thickness of the transparent conductive layer is greater than a thickness of the metal layer.

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