A light-emitting diode structure and a method for manufacturing a light-emitting diode

Abstract

The present disclosure relates to a light-emitting diode structure and a manufacturing method thereof. The light-emitting diode structure includes: a first AlGaInP confinement layer, a multi-quantum well active layer, a second AlGaInP confinement layer, a GaP contact layer, a transparent conductive thin film layer, and a patterned electrode layer sequentially arranged on a GaAs substrate; wherein, the GaP contact layer has a concavo-convex structure, the transparent conductive thin film layer is connected to the GaP contact layer, and a complementary concavo-convex structure is formed at the connection interface; and the position of the electrode portion of the patterned electrode layer is aligned with the position of the concave portion of the GaP contact layer or the convex portion of the transparent conductive thin film layer. According to the light-emitting diode structure and the manufacturing method thereof of the present disclosure, it is possible to ensure stable electrical and optical characteristics of the light-emitting diode during operation, improve the reliability of the product, and enhance the light-emitting efficiency of the light-emitting diode.

Description

Technical Field

[0001] The present application relates to the field of semiconductor light-emitting diodes, and particularly to a high-brightness light-emitting diode with a transparent conductive thin film layer. Background Art

[0002] Light-emitting diodes have advantages such as high luminous efficiency, low energy consumption, long lifespan, high safety, and high environmental friendliness. They are a lighting method with broad application prospects and are being taken more seriously by an increasing number of countries. Currently, light-emitting diodes have been widely used in various categories of solid-state lighting fields, such as display screens, backlights, indoor lighting, outdoor lighting, indicator lights, landscape lighting, and plant lighting.

[0003] Since the light-emitting layer of a conventional AlGaInP light-emitting diode is a GaP layer, and the GaP layer also plays an important role in ohmic contact and current spreading, this will cause the current to easily concentrate and flow through the area directly below the region in contact with the electrode, that is, the current density in the area directly below the electrode increases, and the current cannot be fully spread, reducing the luminous efficiency of the light-emitting diode. For example, the transparent conductive thin film of ITO has good lateral current spreading compared to the GaP layer, and at the same time has advantages such as high transmittance, good conductivity, wear resistance, and corrosion resistance, and has good adhesion to the GaP layer. Therefore, the ITO transparent conductive thin film is usually used as a transparent electrode material to improve the brightness of AlGaInP-based chips. In practical applications, an ITO thin film is grown on the GaP layer, and then a metal electrode layer is deposited. Although this simple manufacturing structure improves the lateral current spreading level, it injects a higher current density into the light-emitting layer in the area below and around the metal electrode than in the area farther from the metal electrode, reducing the effective utilization level of current injection. Summary of the Invention

[0004] The present invention aims to solve the above problems and improve the luminous efficiency of a light-emitting diode with a transparent conductive thin film structure.

[0005] The first aspect of the present invention provides a light-emitting diode structure, including:

[0006] A first AlGaInP confinement layer, a multi-quantum well active layer, a second AlGaInP confinement layer, a GaP contact layer, a transparent conductive thin film layer, and a patterned electrode layer sequentially arranged on a GaAs substrate;

[0007] Wherein, the GaP contact layer has a concavo-convex structure, the transparent conductive thin film layer is connected to the GaP contact layer, and complementary concavo-convex structures are formed at the connection interface; and

[0008] The position of the electrode part of the patterned electrode layer is aligned with the position of the concave part of the GaP contact layer or the convex part of the transparent conductive thin film layer.

[0009] In some embodiments, the GaP contact layer has a non-uniform concave-convex structure, and along the direction away from the electrode portion around the electrode portion, the area ratio of the concave portion to the convex portion of the non-uniform concave-convex structure decreases.

[0010] In some embodiments, the GaP contact layer has a non-uniform concave-convex structure, and along the direction away from the electrode portion around the electrode portion, the area of the concave portion of the non-uniform concave-convex structure gradually decreases and / or the area of the convex portion of the non-uniform concave-convex structure gradually increases.

[0011] In some embodiments, the GaP contact layer has a non-uniform concave-convex structure, and along the direction away from the electrode portion around the electrode portion, the area of the concave portion of the non-uniform concave-convex structure decreases stepwise and / or the area of the convex portion increases stepwise.

[0012] In some embodiments, the transparent conductive thin film layer is ITO or FTO.

[0013] In some embodiments, an AlGaInP stress reaction layer is further provided between the second AlGaInP confinement layer and the GaP contact layer. In the AlGaInP stress reaction layer, the molar ratio of Al atoms to P atoms is x, the molar ratio of Ga atoms to P atoms is y, and the molar ratio of In atoms to P atoms is z. Then, the value of z is greater than 0.5, and x + y + z = 1.

[0014] In some embodiments, the number of layers of the AlGaInP stress reaction layer is n layers. Let the thickness of the i-th layer be di and the value of z be zi. Then, the thickness d of each layer of the stress reaction layer and the In atomic composition ratio z satisfy

[0015] The second aspect of the present invention provides a method for manufacturing a light-emitting diode, including:

[0016] Manufacturing a light-emitting diode epitaxial wafer, which includes a first AlGaInP confinement layer, a multi-quantum well active layer, a second AlGaInP confinement layer, and a GaP contact layer sequentially arranged on a GaAs substrate;

[0017] Patterning the GaP contact layer to form a concave-convex structure on the GaP contact layer;

[0018] Depositing a transparent conductive thin film layer on the GaP contact layer with the concave-convex structure, so that the transparent conductive thin film layer has a complementary concave-convex structure;

[0019] Manufacturing a patterned electrode layer on the transparent conductive thin film layer, so that the position of the electrode portion of the patterned electrode layer is aligned with the position of the concave portion of the GaP contact layer or the convex portion of the transparent conductive thin film layer.

[0020] In some embodiments, fabricating a patterned concavo-convex structure on a GaP contact layer includes:

[0021] Depositing a dielectric film layer on the GaP contact layer;

[0022] Pattern the dielectric film layer;

[0023] Etch the area of the GaP contact layer that is not protected by the dielectric film layer using a GaP etchant; and

[0024] Remove the dielectric film layer using a dielectric film etchant to obtain a GaP contact layer with a concavo-convex structure.

[0025] In some embodiments, when fabricating a patterned concavo-convex structure on a GaP contact layer, the area ratio of the concave part to the convex part of the patterned concavo-convex structure decreases in a direction away from the electrode part around the electrode part.

[0026] According to the light-emitting diode structure and its manufacturing method of the present disclosure, by providing a patterned GaP contact layer and depositing a transparent conductive thin film layer thereon, complementary concavo-convex structures are formed at the connection interface between the transparent conductive thin film layer and the GaP contact layer, and the position of the electrode part of the patterned electrode layer is aligned with the position of the concave part of the GaP contact layer or the convex part of the transparent conductive thin film layer. Therefore, the injection current can be expanded and uniformly injected into the effective light-emitting region, improving the effective utilization level of the current injection, ensuring the stable electrical and optical characteristics of the light-emitting diode during operation, enhancing the reliability of the product, and improving the light-emitting efficiency of the light-emitting diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Shows a schematic cross-sectional structure diagram of a light-emitting diode according to an embodiment of the present invention.

[0028] Figure 1a Shows a schematic cross-sectional structure diagram of a light-emitting diode according to another embodiment of the present invention.

[0029] Figure 1b Shows a schematic cross-sectional structure diagram of a light-emitting diode according to another embodiment of the present invention.

[0030] Figure 2 Shows as Figure 1 shown, a flowchart of the manufacturing method of the light-emitting diode.

[0031] Figure 2a Shows as Figure 2 shown, the specific steps of step S2 of the manufacturing method of the light-emitting diode.

[0032] Figure 3Shows a schematic cross-sectional structure diagram of a light-emitting diode according to another embodiment of the present invention.

[0033] Figure 4 Shows a schematic cross-sectional structure diagram of a light-emitting diode according to a specific embodiment.

[0034] Figures 4a to 4d Shows Figure 4 Schematic structural diagram of the manufacturing process of the light-emitting diode of. Detailed implementation manners

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Unless otherwise defined, in the embodiments of the present invention and the accompanying drawings, the same reference numerals represent the same meaning. It should be noted that, for clarity, the drawings of the embodiments may not necessarily be drawn to scale; in addition, in the drawings of some embodiments of the present invention, only the structures related to the concept of the present invention are shown, and the illustrations of some conventional structures and details that have no direct relation to the concept of the present invention may be omitted. The embodiments of the present invention may include these structures not shown. Also, it should be noted that the order of the method steps described in the embodiments of the present invention does not necessarily represent the actual execution order of each step. Where feasible, the actual execution order may be different from the described order.

[0036] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meaning understood by those of ordinary skill in the field to which the present invention pertains. The "first", "second", and similar terms used in the present invention do not denote any order, quantity, or importance, but are only used to distinguish different components. The terms such as "comprising" or "including" denote an open meaning and do not exclude other elements, components, parts, or items in addition to the explicitly listed elements, components, parts, or items. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly. It can be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "under" another element, the element may be "directly" on or under the other element, or there may be intermediate elements.

[0037] As Figure 1 Shown, shows a schematic cross-sectional view of the main structure of an AlGaInP light-emitting diode 20 according to an embodiment of the present invention. As Figure 1As shown, the AlGaInP light-emitting diode 20 includes a first AlGaInP confinement layer 203, a multi-quantum well active layer 204, a second AlGaInP confinement layer 205, a GaP contact layer 210, a transparent conductive thin film layer 211, and a patterned electrode layer 212 that are sequentially arranged on a GaAs substrate 200. The transparent conductive thin film layer 211 can be ITO; alternatively, the transparent conductive thin film layer can also be FTO or other materials with similar functions to ITO. The multi-quantum well active layer 204 can adopt a quantum well structure that meets the requirements of the AlGaInP light-emitting diode. The material of the patterned electrode layer 212 can be selected from any one of the metals Cr, Pt, Ni, Ti, Al, Cu, Au, Ag or any combination thereof.

[0038] As Figure 1 shown, the GaP contact layer 210 has a patterned concave-convex structure, and the transparent conductive thin film layer 211 is connected to the GaP contact layer 210 with the concave-convex structure, and complementary concave-convex structures are formed at the connection interface. That is, the concave portion 210a of the GaP contact layer 210 corresponds to the convex portion 211b of the transparent conductive thin film layer 211; the convex portion 210b of the GaP contact layer 210 corresponds to the concave portion 211a of the transparent conductive thin film layer 211. Moreover, the position of the electrode portion 212a of the patterned electrode layer 212 is aligned with the position of a concave portion 210a of the GaP contact layer 210 or a convex portion 211b of the transparent conductive thin film layer 211.

[0039] Note that Figure 1 only the diode structure unit around one electrode portion 210a is shown. The electrode portion 210a can be cylindrical. The concave portion 210a of the GaP contact layer 210 or the convex portion 211b of the transparent conductive thin film layer 211 directly below the electrode portion 210a can have a circular planar shape corresponding to the planar shape of the electrode portion 210a. Accordingly, the planar shape of the concave portion 210a of the GaP contact layer 210 or the convex portion 211b of the transparent conductive thin film layer 211 around the electrode portion 210a can be in the shape of a concentric ring surrounding the electrode portion 210a. Of course, the cross-section of the electrode portion can also be other shapes according to needs, such as triangular, rectangular, irregular shapes, etc.; accordingly, the concave portion 210a of the GaP contact layer 210 or the convex portion 211b of the transparent conductive thin film layer 211 around the electrode portion 210a adopt similar planar shapes.

[0040] In this embodiment, since the ITO or FTO transparent conductive thin film layer 211 with ohmic contact and current spreading functions is connected to the patterned GaP contact layer 210, a recess 210a of the GaP contact layer 210 is formed by removing a part of the GaP contact layer in the area below the metal electrode part 212a, and the ITO or FTO transparent conductive thin film layer 211 fills the recess of the GaP contact layer 210 to form a convex part 211b of the ITO or FTO transparent conductive thin film layer 211. Therefore, in the area below the metal electrode part 212a, the current impedance is increased at the recess 210a of the GaP contact layer 210 or the convex part 211b of the transparent conductive thin film layer 211, the current density in the area directly below the electrode is reduced, so that the injected current spreads and is uniformly injected into the effective light-emitting area, improving the effective utilization level of current injection, ensuring the stable electrical and optical characteristics of the light-emitting chip during operation, improving the reliability of the product, enhancing the light-emitting efficiency of the light-emitting diode, and greatly improving the quality of the product.

[0041] Furthermore, in a specific embodiment, the GaP contact layer 210 has a non-uniform concave-convex structure, such that the area ratio of the recess 210a to the convex part 210b of the GaP contact layer 210 decreases in the direction away from the electrode part 212a around the electrode part 212a. Specifically, as Figure 1 shown, in the direction away from the electrode part around the electrode part, the area (horizontal cross-sectional area) of the recess 210a of the GaP contact layer 210 can gradually decrease from near to far, while the area (horizontal cross-sectional area) of the convex part 210b of the GaP contact layer 210 remains unchanged.

[0042] Figure 1a FIG. shows a cross-sectional schematic diagram of the main structure of an AlGaInP light-emitting diode 20a according to another embodiment of the present invention. As Figure 1a shown, in the direction away from the electrode part 212a around the electrode part 212a, the area of the convex part 210b of the GaP contact layer 210 can gradually increase from near to far, while the area of the recess 210a of the GaP contact layer 210 remains unchanged.

[0043] Figure 1b FIG. shows a cross-sectional schematic diagram of the main structure of an AlGaInP light-emitting diode 20b according to another embodiment of the present invention. As Figure 1b shown, in the direction away from the electrode part around the electrode part, the area of the recess 210a of the GaP contact layer 210 can decrease stepwise, and at the same time, the area of the convex part 210b of the GaP contact layer 210 can increase stepwise. Here, the stepwise increase or decrease means that the areas of multiple recesses 210a or multiple convex parts 210b do not change continuously but stepwise.

[0044] According to the above embodiments, since the area ratio of the concave portions 210a and the convex portions 210b of the GaP contact layer 210 gradually decreases from near to far in a direction away from the electrode portion around the metal electrode portion, the injection current is further effectively expanded around the metal electrode portion and uniformly injected into the effective light-emitting region, further improving the effective utilization level of current injection and enhancing the light-emitting efficiency of the light-emitting diode.

[0045] Figure 2 shows a method for manufacturing the light-emitting diode 20 as Figure 1 shown. As Figure 2 shown, the method for manufacturing the light-emitting diode includes the following steps:

[0046] S1: Fabricate a light-emitting diode epitaxial wafer, which includes a first AlGaInP confinement layer, a multi-quantum well active layer, a second AlGaInP confinement layer, and a GaP contact layer sequentially arranged on a GaAs substrate;

[0047] S2: Pattern the GaP contact layer to form a concavo-convex structure on the GaP contact layer;

[0048] S3: Deposit a transparent conductive thin film layer on the GaP contact layer with the concavo-convex structure, such that the transparent conductive thin film layer has a complementary concavo-convex structure;

[0049] S4: Fabricate a patterned electrode layer on the transparent conductive thin film layer, such that the position of the electrode portion of the patterned electrode layer is aligned with the position of the concave portion of the GaP contact layer or the convex portion of the transparent conductive thin film layer.

[0050] Specifically, as Figure 2a shown, in step S2, patterning the GaP contact layer to form a concavo-convex structure on the GaP contact layer specifically includes:

[0051] S21: Deposit a dielectric film layer on the GaP contact layer;

[0052] S22: Pattern the dielectric film layer by photolithography and etching;

[0053] S23: Etch the area of the GaP contact layer without the protection of the dielectric film layer using a GaP etchant; and

[0054] S24: Remove the dielectric film layer using a dielectric film etchant to obtain a GaP contact layer with a concavo-convex structure.

[0055] Further, when forming the patterned dielectric film layer or fabricating the patterned concavo-convex structure on the GaP contact layer, the area ratio of the concave portion to the convex portion of the patterned concavo-convex structure is decreased in a direction away from the electrode portion around the electrode portion.

[0056] To this end, optionally, around the electrode portion, in a direction away from the electrode portion, from near to far, the area of the concave portion 210a of the GaP contact layer 210 may be gradually reduced, while the area of the convex portion 210b of the GaP contact layer 210 remains unchanged; or, around the electrode portion, in a direction away from the electrode portion, from near to far, the area of the convex portion 210b of the GaP contact layer 210 may be gradually increased, while the area of the concave portion 210a of the GaP contact layer 210 remains unchanged; or, around the electrode portion, in a direction away from the electrode portion, from near to far, the area of the concave portion 210a of the GaP contact layer 210 may be gradually reduced, and at the same time the area of the convex portion 210b of the GaP contact layer 210 may be gradually increased.

[0057] Optionally, around the electrode portion, in a direction away from the electrode portion, the area of the concave portion 210a of the GaP contact layer 210 may be stepwise reduced, while the area of the convex portion 210b of the GaP contact layer 210 remains unchanged; or, around the electrode portion, in a direction away from the electrode portion, the area of the convex portion 210b of the GaP contact layer 210 may be stepwise increased, while the area of the concave portion 210a of the GaP contact layer 210 remains unchanged; or, around the electrode portion, in a direction away from the electrode portion, the area of the concave portion 210a of the GaP contact layer 210 may be stepwise reduced, and at the same time the area of the convex portion 210b of the GaP contact layer 210 may be stepwise increased.

[0058] On the other hand, the inventors of the present invention also found through research that when using a GaP layer as a current spreading layer and an ohmic contact layer, since the lattice constant of GaP at room temperature is 0.545 nm, which is 3.6% smaller than the lattice constant of the GaAs substrate (0.565 nm), and usually the thickness reaches more than 1.5 microns, it generates compressive stress on the light-emitting active layer (mainly including a p-AlGaInP confinement layer, an MQW multi-quantum well layer, and an n-AlGaInP layer), inducing lattice defects in it, thereby reducing the electro-optical conversion efficiency of the light-emitting active layer.

[0059] To solve the above problems, in one embodiment, as Figure 3 shown, between the second AlGaInP confinement layer 205 and the GaP contact layer 210 shown in Figure 1 a layer of AlGaInP stress reaction layer 206 is added. Figure 3 Other aspects of the embodiment shown in Figure 1 are the same as those of the embodiment shown in

[0060] In this embodiment, since the AlGaInP stress reaction layer 206 reversely blocks the stress of the GaP lattice mismatch layer, the compressive stress on the light-emitting active layers 204, 205, and 206 is reduced, and the lattice defect density thereof is decreased. Therefore, the electro-optical conversion efficiency of the light-emitting active layer is improved, thereby further enhancing the light-emitting efficiency of the light-emitting diode.

[0061] In this embodiment, specifically in implementation, the number of layers of the AlGaInP stress reaction layer 206 can be set to one layer or multiple layers. When the number of layers of the AlGaInP stress reaction layer 206 is multiple layers, assuming the thickness of the i-th layer is di and the z value is zi, the thickness d and the In atomic composition ratio z of each layer of the stress reaction layer 206 satisfy

[0062] When the number of layers increases, the stress of the GaP lattice mismatch layer can be better blocked, the lattice defects of the light-emitting active layer can be better improved, and the electro-optical conversion efficiency of the light-emitting active layer can be enhanced; however, the increase in the number of layers will increase the production complexity and raise the production cost. Therefore, the number of layers of the AlGaInP stress reaction layer 206 can be set to 2 - 10 layers; preferably, it can be set to 2 - 3 layers, or 2 - 4 layers, 2 - 5 layers, 2 - 6, 2 - 7 layers, etc. The thickness of each layer is in the range of 100 - 400 nm.

[0063] Figure 4 The cross-sectional schematic diagram showing the manufacturing process of an AlGaInP light-emitting diode according to a specific embodiment is shown. As Figure 4 shown, the AlGaInP light-emitting diode 10 includes a GaAs substrate 100 and, sequentially arranged on one side of the GaAs substrate 100, a buffer layer 101, a DBR (distributed Bragg) reflection layer 102, an n-AlGaInP confinement layer 103, a multi-quantum well (MQW) active layer 104, a p-AlGaInP confinement layer 105, a p-AlGaInP stress reaction layer 106, a p-GaP window layer 107, a p-GaP contact layer 110, an ITO transparent conductive thin film layer 111, and a patterned electrode layer 112.

[0064] As Figure 4As shown, the GaP contact layer 110 has a patterned concavo-convex structure. The transparent conductive thin film layer 111 is connected to the GaP contact layer 110 with the concavo-convex structure, and complementary concavo-convex structures are formed at the connection interface. That is, the concave portion 110a of the GaP contact layer 110 corresponds to the convex portion 111b of the transparent conductive thin film layer 111; the convex portion 110b of the GaP contact layer 110 corresponds to the concave portion 111a of the transparent conductive thin film layer 111. Moreover, the position of the electrode portion 112a of the patterned electrode layer 112 is aligned with the position of one concave portion 110a of the GaP contact layer 110 or one convex portion 111b of the transparent conductive thin film layer 111.

[0065] Furthermore, in the above embodiment, along the direction away from the electrode portion 112a around the electrode portion 112a, the area of the concave portion 110a of the GaP contact layer 110 decreases step by step, while the area of the convex portion 110b of the GaP contact layer 110 increases step by step. Optionally, in other embodiments, along the direction away from the electrode portion around the electrode portion, from near to far, the area of the concave portion 110a of the GaP contact layer 110 can be gradually reduced, while the area of the convex portion 110b of the GaP contact layer 110 remains unchanged; or, along the direction away from the electrode portion around the electrode portion, from near to far, the area of the convex portion 110b of the GaP contact layer 110 can be gradually increased, while the area of the concave portion 110a of the GaP contact layer 110 remains unchanged; or, along the direction away from the electrode portion around the electrode portion, from near to far, the area of the concave portion 210a of the GaP contact layer 210 can be gradually reduced, and at the same time the area of the convex portion 210b of the GaP contact layer 210 can be gradually increased, and so on. As long as the area ratio of the concave portion 210a and the convex portion 210b of the GaP contact layer 210 is gradually reduced from near to far around the metal electrode portion, the injected current can be effectively expanded around the metal electrode portion and uniformly injected into the effective light-emitting region, further improving the effective utilization level of the current injection and enhancing the light-emitting efficiency of the light-emitting diode.

[0066] As Figures 4a - 4d shown, the manufacturing method of a light-emitting diode with the Figure 4 structure shown is as follows:

[0067] First, as Figure 4a shown, on one side of the GaAs substrate 100, a buffer layer 101, a DBR reflective layer 102, an n-AlGaInP confinement layer 103, a multi-quantum well active layer 104, a p-AlGaInP confinement layer 105, a p-AlGaInP stress reaction layer 106, a p-GaP window layer 107, and a P-GaP contact layer 110 are sequentially epitaxially grown by metalorganic chemical vapor deposition (MOCVD) to obtain the structure as Figure 3The light-emitting diode epitaxial wafer shown. The thickness of the surface highly doped layer of the p-GaP contact layer 110 is preferably 150 ± 20 Å, and the doping concentration is preferably above 1×10 19 cm-3. The stress reaction layer is p-Al(0.2)Ga(0.25)In(0.55)P.

[0068] Next, a non-uniformly patterned concave-convex structure is fabricated on the p-GaP contact layer 110, specifically including: growing a dielectric film layer on the entire p-GaP contact layer 110 by PECVD (plasma-enhanced chemical vapor deposition method), and the thickness of the dielectric film layer 109 is preferably 2500 ± 300 Å; then, a patterned dielectric film layer 109 is fabricated by photolithography and etching, as Figure 4b shown. The dielectric film layer fabricated by PECVD is made of insulating materials such as SiO2 or SiNxOy, where x > 0 and 0 < y < 2. A stable patterned temporary film layer is obtained to avoid being affected by the etching of the p-GaP contact layer.

[0069] When fabricating the non-uniformly patterned dielectric film layer 109, the position of the dielectric film layer 109 corresponding to the electrode part to be provided is patterned into a concave part; and symmetric concave-convex structures are alternately formed around it, so that the area ratio of the concave part to the convex part decreases in the direction away from the electrode part.

[0070] Next, the area of the p-GaP contact layer 110 not protected by the dielectric film layer 109 is etched with a GaP etching solution, and then the dielectric film layer 109 is removed with a dielectric film etching solution to obtain a patterned p-GaP contact layer 110, as Figure 4c shown. Here, although the figure shows that the GaP layer in the concave part area is completely removed, the GaP layer in the concave part area does not have to be completely removed. The etching depth of the GaP layer can be 200 ± 30 nm, so that both the highly doped layer can be removed and the step difference in the area around the contact layer is large, making it easy to fabricate the metal electrode layer.

[0071] Then, an ITO transparent conductive thin film layer is deposited by evaporation coating method on the p-GaP contact layer 110 with a patterned concave-convex structure. The thickness of the ITO transparent conductive thin film layer 111 is preferably 3000 ± 300 Å. The lower surface of the obtained ITO transparent conductive thin film layer has a concave-convex structure complementary to the concave-convex structure of the p-GaP contact layer 110; then, a patterned metal electrode layer 112 is fabricated by evaporation coating on the upper surface of the patterned ITO transparent conductive thin film layer 111. Specifically, a negative photoresist lift-off and evaporation coating method is used to fabricate the metal main electrode layer 112, and the obtained is as Figure 4dThe film layer structure shown. The shape of the electrode portion 112a of the metal electrode layer 112 can be cylindrical, with a circular horizontal cross-section, a diameter of 80 ± 10 um, the material is Cr / Au, and the thickness is (30 ± 10) / (2500 ± 300) nm.

[0072] Finally, an n-electrode layer 201 is fabricated on the other side of the GaAs substrate 100 by evaporation coating method to obtain the Figure 4 AlGaInP light-emitting diode structure 10 shown. The electrode material of the n-electrode layer 201 can be AuGeNi / Au, and the thickness is (180 ± 20) / (250 ± 30) nm. Then, fusion is carried out in a nitrogen atmosphere at 430 ± 15 °C to obtain a good ohmic contact between the n-electrode 201 and the GaAs substrate 100, and at the same time, the excellent contact characteristics and adhesion between the metal electrode layer 112, the patterned ITO thin film layer 111, and the patterned p-GaP contact layer 110 are further enhanced.

[0073] In this embodiment, a patterned dielectric film layer 109 is fabricated by photolithography and etching methods, and then the p-GaP contact layer 110 in the area without the dielectric film layer is etched with a controllable depth by etching method; secondly, an ITO transparent conductive thin film layer 111 and a corresponding metal electrode layer 112 are evaporated on the patterned p-GaP contact layer 110, so that the position of the electrode portion 112a of the patterned electrode layer 112 is aligned with the position of a concave portion 110a of the GaP contact layer 110 or a convex portion 111b of the transparent conductive thin film layer 111; and, along the direction away from the electrode portion 112a around the electrode portion 112a, the area ratio of the concave portion 110a to the convex portion 110b of the GaP contact layer 110 decreases, so that the injected current is expanded and uniformly injected into the effective light-emitting region, improving the effective utilization level of the current injection, and further improving the light-emitting efficiency of the light-emitting diode.

[0074] At the same time, since an AlGaInP stress reaction layer 206 is added between the second AlGaInP confinement layer 106 and the GaP contact layer 210, the AlGaInP stress reaction layer 106 reversely blocks the stress of the GaP lattice mismatch layer, reducing the compressive stress on the light-emitting active layer including the n-AlGaInP confinement layer 103, the multi-quantum well (MQW) active layer 104, and the p-AlGaInP confinement layer 105, and reducing its lattice defect density. Therefore, the electro-optical conversion efficiency of the light-emitting active layer is improved, and thus the light-emitting efficiency of the light-emitting diode is further improved.

[0075] In summary, the embodiments of the present invention provide a light-emitting diode with a transparent conductive thin film structure that is convenient for manufacturing, has low lattice stress, high current injection effectiveness, high light-emitting efficiency, and high reliability.

[0076] The principles and configurations of the present invention have been described above through embodiments. It should be understood that the above embodiments are merely examples of the present invention and are not used to limit the present invention. Where feasible, local combinations may be made between different embodiments. Without departing from the general concept of the present invention, any changes and improvements made to the present invention fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the scope defined by the claims of this application.

Claims

1. A light-emitting diode structure, comprising: a first AlGaInP confinement layer, a multi-quantum well active layer, a second AlGaInP confinement layer, a GaP contact layer, a transparent conductive thin film layer, and a patterned electrode layer sequentially arranged on a GaAs substrate; wherein, the GaP contact layer has a concavo-convex structure, the transparent conductive thin film layer is connected to the GaP contact layer, and a complementary concavo-convex structure is formed at the connection interface; and the position of the electrode portion of the patterned electrode layer is aligned with the position of the concave portion of the GaP contact layer or the convex portion of the transparent conductive thin film layer; wherein, the GaP contact layer has a non-uniform concavo-convex structure, and the area ratio of the concave portion to the convex portion of the non-uniform concavo-convex structure decreases in a direction away from the electrode portion around the electrode portion.

2. The light-emitting diode structure according to claim 1, wherein, the GaP contact layer has a non-uniform concavo-convex structure, and the area of the concave portion of the non-uniform concavo-convex structure gradually decreases and / or the area of the convex portion of the non-uniform concavo-convex structure gradually increases in a direction away from the electrode portion around the electrode portion.

3. The light-emitting diode structure according to claim 1, wherein, the GaP contact layer has a non-uniform concavo-convex structure, and the area of the concave portion of the non-uniform concavo-convex structure decreases stepwise and / or the area of the convex portion of the non-uniform concavo-convex structure increases stepwise in a direction away from the electrode portion around the electrode portion.

4. The light-emitting diode structure according to claim 1, wherein, the transparent conductive thin film layer is ITO or FTO.

5. The light-emitting diode structure according to any one of claims 1-4, wherein, an AlGaInP stress reaction layer is further provided between the second AlGaInP confinement layer and the GaP contact layer. In the AlGaInP stress reaction layer, the molar ratio of Al atoms to P atoms is x, the molar ratio of Ga atoms to P atoms is y, and the molar ratio of In atoms to P atoms is z. Then the value of z is greater than 0.5, and x + y + z = 1.

6. The light-emitting diode structure according to claim 5, wherein, The number of layers of the AlGaInP stress reaction layer is multiple. Assuming that the thickness of the i-th layer is di and the z value is zi, the thickness d and the In atomic composition ratio z of each layer of the stress reaction layer satisfy 7. A manufacturing method of a light-emitting diode, comprising: manufacturing a light-emitting diode epitaxial wafer, the light-emitting diode epitaxial wafer including a first AlGaInP confinement layer, a multi-quantum well active layer, a second AlGaInP confinement layer, and a GaP contact layer sequentially arranged on a GaAs substrate; pattern the GaP contact layer to form a concavo-convex structure on the GaP contact layer; deposit a transparent conductive thin film layer on the GaP contact layer having a concavo-convex structure, so that the transparent conductive thin film layer has a complementary concavo-convex structure; manufacture a patterned electrode layer on the transparent conductive thin film layer, so that the position of the electrode portion of the patterned electrode layer is aligned with the position of the concave portion of the GaP contact layer or the convex portion of the transparent conductive thin film layer; wherein, when manufacturing the patterned concavo-convex structure on the GaP contact layer, the area ratio of the concave portion to the convex portion of the patterned concavo-convex structure decreases in a direction away from the electrode portion around the electrode portion.

8. The manufacturing method of a light-emitting diode according to claim 7, wherein, Fabricating a patterned concave-convex structure on a GaP contact layer, including: Depositing a dielectric film layer on the GaP contact layer; Patternizing the dielectric film layer; Etching the area of the GaP contact layer without the protection of the dielectric film layer using a GaP etchant; and Removing the dielectric film layer using a dielectric film etchant to obtain a GaP contact layer with a concave-convex structure.

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