Light-emitting diode device structure with sidewall field plate and preparation method thereof

Abstract

The present invention relates to a light-emitting diode device structure with a sidewall field plate and a preparation method thereof. The sidewall field plate structure is composed of an insulating layer and an anode electrode covered on the insulating layer; the insulating layer covers the current expansion layer, the hole transport layer, the electron blocking layer and the side wall of the active region and the upper surface of the electron transport layer in the light-emitting diode mesa; the width of the insulating layer from the electron blocking layer to the side wall of the current expansion layer in the light-emitting diode mesa is 0.001 to 1 μm, and the width of the insulating layer on the upper surface of the electron transport layer is greater than the width of the insulating layer from the electron blocking layer to the side wall of the current expansion layer; the sidewall field plate structure is used to deplete the edge carriers of the light-emitting diode device and reduce the carrier concentration at the edge of the device, so that the non-radiative recombination at the edge of the device can be weakened, so that the carriers of the entire device can be effectively utilized, and finally the light power of the light-emitting diode device, especially the small-sized light-emitting diode device, can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of light emitting diode semiconductors, in particular to a light emitting diode device structure with a side wall field plate and a preparation method thereof. Background Art

[0002] Light-emitting diode (LED) technology has the advantages of low power consumption, long service life, bright colors, and green environmental protection. It has shown broad application prospects in the fields of sterilization, biomedicine, lighting, display and communication. However, the technology of preparing LED using III-V wide bandgap semiconductor materials, small molecule and polymer organic materials, inorganic quantum dot materials, etc. still faces many problems that need to be solved urgently. Among them, the defects at the edge of the LED table lead to serious leakage and non-radiative recombination of the device, which is one of the problems that need to be solved urgently. The main reason for this phenomenon is that when the LED structure is lithographically and inductively coupled plasma dry etching is performed, the exposed table edge of the device will be severely damaged. The hanging key formed at the edge of the table is easy to absorb impurities in the air, forming a defect state, resulting in an increase in the defect density at the edge of the device (i.e., a leakage channel is formed at the edge of the device), and the carriers flowing through the edge of the device will be captured by the defects in large quantities, resulting in serious leakage, thereby reducing the number of carriers participating in radiative recombination, reducing the luminous efficiency of the device, and also reducing the reliability of the device. In order to suppress the leakage phenomenon at the edge of the LED table, the researchers conducted a series of research, such as using NO2, SIN x Thin film materials, ammonium sulfide aqueous solution, and a mixed solution of ammonium sulfide and tert-butyl alcohol are used to passivate the side wall of the LED table to reduce the leakage current at the edge of the device [C. Huh, SW Kim, HCKim, et al. Effects of sulfur treatment on electrical and optical performance of InGaN / GaN multiple-quantum-well blue light-emitting diodes. Appl. Phys. Lett., 2001, 78 (12): 1766-1768]; In addition, a Chinese patent with patent number CN108461593B discloses a GaN-based light-emitting diode with a nano-scale silicon dioxide grating passivation layer and a processing method thereof. The patent protects the surface of the light-emitting diode by depositing a SiO2 passivation layer on the side wall of the light-emitting diode protrusion structure and limits the generation of leakage current. Although the above-mentioned passivation layers inhibit the defect recombination at the edge of the light-emitting diode device to a certain extent, the improvement effect on the photoelectric performance of the device is not good. Summary of the invention

[0003] The object of the present invention is to provide a light-emitting diode device structure with a sidewall field plate and a preparation method thereof, aiming at the existing technical deficiencies. The present invention combines any existing standard light-emitting diode mesa with a sidewall field plate structure to enhance the edge electric field of the light-emitting diode device, reduce the originally high carrier concentration at the edge of the LED mesa, thereby weakening the leakage current generated at the edge of the device, effectively enhancing the radiative recombination rate inside the LED, and improving the light-emitting efficiency of the LED.

[0004] The technical solution adopted by the present invention to solve this technical problem is as follows:

[0005] A light-emitting diode device structure with a sidewall field plate, characterized in that the sidewall field plate structure is composed of an insulating layer (109) and an anode electrode (111) covering the insulating layer; a sidewall field plate structure is provided on the upper surface of the electron transport layer (103) and the sidewall from the electron blocking layer (105) to the current spreading layer (107) in the light-emitting diode mesa; or a sidewall field plate structure is provided on the upper surface of the electron transport layer (103), the sidewall from the electron blocking layer (105) to the current spreading layer (107), and the edge of the upper surface of the current spreading layer (107) in the light-emitting diode mesa.

[0006] For the light-emitting diode device structure with a sidewall field plate of the present invention, the height (H1) of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer (103) and the upper surface of the active region layer (104), and the width (W1) of the insulating layer covering the upper surface of the electron transport layer is 0.001 - 500 μm; the height (H2) of the insulating layer covering the sidewall from the electron blocking layer to the current spreading layer is the sidewall height from the electron blocking layer (105) to the current spreading layer (107), and the width (W2) of the insulating layer covering the sidewall from the electron blocking layer to the current spreading layer is 0.001 - 1 μm, where W2 < W1; the height (H3) of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 - 1 μm, and the width (W3) of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 - 200 μm.

[0007] The light-emitting diode device structure with a sidewall field plate of the present invention is characterized in that the sidewall field plate structure can simultaneously cover a part of the cathode electrode (108).

[0008] For the light-emitting diode device structure with a sidewall field plate of the present invention, the height (H4) of the insulating layer covering the upper surface of the cathode electrode is the distance between the upper surface of the cathode electrode (108) and the upper surface of the active region layer (104), and the width (W4) of the insulating layer covering the upper surface of the cathode electrode is 0.1% - 90% of the width of the cathode electrode (108).

[0009] The light-emitting diode device structure with sidewall field plates of the present invention, wherein the material used for the insulating layer (109) in the sidewall field plate structure is non-doped SiO2, Al2O3, Si3N4, HfO2, Ta2O5, AlN, LiF, diamond or PMMA.

[0010] The light-emitting diode device structure with sidewall field plates of the present invention has an anode electrode (111) covered on an insulating layer in the sidewall field plate structure and an anode electrode (110) covered on a current spreading layer in a standard light-emitting diode made of the same material, which are Au, ITO, Ni / Au, Cr / Au, Pt / Au or Ni / Al.

[0011] The light-emitting diode device structure with a sidewall field plate of the present invention, wherein the coverage of the anode electrode (111) covered on the insulating layer in the sidewall field plate structure does not include the sidewall of the insulating layer (109) prepared on the upper surface of the electron transport layer (103) and the upper surface of the cathode electrode (108); the anode electrode (111) covered on the insulating layer and the anode electrode (110) covered on the current expansion layer in a standard light-emitting diode can be connected to form one anode electrode or separated into two independent anode electrodes; the thickness of the anode electrode (111) covered on the insulating layer is the same as the thickness of the anode electrode (110) covered on the current expansion layer in a standard light-emitting diode.

[0012] The light emitting diode device structure with sidewall field plates of the present invention is characterized in that the light emitting diode mesa is any one of standard light emitting diodes, and the size of the light emitting diode mesa is 1 to 1000 μm; the standard light emitting diode device structure mainly comprises a substrate (101), a buffer layer (102), an electron transport layer (103), an active region layer (104), an electron blocking layer (105), a hole transport layer (106), a current expansion layer (107), a cathode electrode (108), and an anode electrode (110) covering the current expansion layer.

[0013] The light-emitting diode device structure with sidewall field plates of the present invention is characterized in that the active region layer (104) includes but is not limited to a multi-quantum well structure, a quantum dot layer, a perovskite layer or an organic layer.

[0014] The light-emitting diode device structure with a sidewall field plate of the present invention, when the sidewall field plate structure does not cover the cathode electrode (108), the preparation method comprises the following steps:

[0015] 1) Using light-emitting diode epitaxial technologies such as evaporation, deposition, or liquid-phase spin coating, a buffer layer (102), an electron transport layer (103), an active region layer (104), an electron blocking layer (105), a hole transport layer (106), and a current spreading layer (107) are sequentially epitaxially grown on the surface of a substrate (101) to obtain an epitaxial layer structure of a light-emitting diode;

[0016] 2) The epitaxial layer structure is etched by photolithography and dry etching processes to the electron transport layer (103) to fabricate a light-emitting diode mesa;

[0017] 3) By means of evaporation, deposition, or liquid-phase spin coating, an insulating layer (109) is deposited or spin-coated on the obtained light-emitting diode mesa;

[0018] 4) An insulating layer pattern in the sidewall field plate structure is fabricated by photolithography and wet etching techniques. The height (H1) of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer (103) and the upper surface of the active region layer (104). The width (W1) of the insulating layer covering the upper surface of the electron transport layer is 0.001 - 500 μm. The height (H2) of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is the sidewall height from the electron blocking layer (105) to the current spreading layer (107). The width (W2) of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is 0.001 - 1 μm, where W2 < W1. The height (H3) of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 - 1 μm. The width (W3) of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 - 200 μm;

[0019] 5) An anode electrode (110) covering the current spreading layer and an anode electrode (111) covering the insulating layer are fabricated by photolithography and evaporation;

[0020] 6) A cathode electrode (108) covering the electron transport layer (103) is fabricated by photolithography and evaporation.

[0021] For the light-emitting diode device structure with a sidewall field plate according to the present invention, when the sidewall field plate structure covers a part of the cathode electrode (108), the preparation steps are basically the same as the above steps. The difference is that the above step 6) is completed before the above step 3). The specific preparation method includes the following steps:

[0022] 1) Using light-emitting diode epitaxial technologies such as evaporation, deposition, or liquid-phase spin coating, a buffer layer (102), an electron transport layer (103), an active region layer (104), an electron blocking layer (105), a hole transport layer (106), and a current spreading layer (107) are sequentially epitaxially grown on the surface of a substrate (101) to obtain an epitaxial layer structure of a light-emitting diode;

[0023] 2) The epitaxial layer structure is etched to the electron transport layer (103) through photolithography and dry etching processes to fabricate a light-emitting diode mesa;

[0024] 3) A cathode electrode (108) covering the electron transport layer (103) is fabricated through photolithography and evaporation;

[0025] 4) An insulating layer (109) is deposited or spin-coated on the obtained light-emitting diode mesa covered with the cathode electrode (108) by means of evaporation, deposition, or liquid-phase spin coating;

[0026] 5) An insulating layer pattern in the sidewall field plate structure is fabricated through photolithography and wet etching techniques. The height (H1) of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer (103) and the upper surface of the active region layer (104). The width (W1) of the insulating layer covering the upper surface of the electron transport layer is 0.001 - 500 μm. The height (H2) of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is the sidewall height from the electron blocking layer (105) to the current spreading layer (107). The width (W2) of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is 0.001 - 1 μm, where W2 < W1. The height (H3) of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 - 1 μm. The width (W3) of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 - 200 μm. The height (H4) of the insulating layer covering the upper surface of the cathode electrode is the distance between the upper surface of the cathode electrode (108) and the upper surface of the active region layer (104). The width (W4) of the insulating layer covering the upper surface of the cathode electrode is 0.1% - 90% of the width of the cathode electrode (108);

[0027] 6) An anode electrode (110) covering the current spreading layer and an anode electrode (111) covering the insulating layer are fabricated through photolithography and evaporation.

[0028] The beneficial effects of the present invention are as follows:

[0029] (1) Compared with the prior art, in the light-emitting diode device structure with a sidewall field plate in the present invention, the sidewall field plate structure is ingeniously combined with a standard light-emitting diode device. By utilizing the characteristic of the sidewall field plate structure to deplete the carrier concentration at the edge of the light-emitting diode device, the light-emitting efficiency of the light-emitting diode device is improved. The formed sidewall field plate structure can generate a certain depletion region at the edge of the light-emitting diode device, effectively reducing the carrier concentration at the edge of the device, thereby weakening the non-radiative recombination phenomenon at the edge part of the device, enabling the carriers of the entire device to be effectively utilized, and ultimately increasing the optical power of the light-emitting diode.

[0030] (2) The method for preparing the light-emitting diode device structure with a sidewall field plate in the present invention is easy to operate, has a simple and reliable process, strong repeatability, low production cost, and is suitable for industrial promotion.

[0031] The light emitting diode structure with the sidewall field plate in the present invention is specially suitable for optoelectronic semiconductor devices, and is particularly suitable for III-V group wide bandgap semiconductor light emitting diode devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the device structure of a standard light emitting diode in the prior art.

[0033] Figure 2 Schematic diagram of the device structure of the light emitting diode with sidewall field plates in Example 1.

[0034] Figure 3 Schematic diagram of the device structure of the light emitting diode with sidewall field plates in Example 2.

[0035] Figure 4 Schematic diagram of the device structure of the light emitting diode with sidewall field plates in Example 3.

[0036] Figure 5 Schematic diagram of the device structure of a light emitting diode with a sidewall field plate according to Example 4.

[0037] Figure 6 In the method of the present invention, a substrate having Figure 2 or Figure 3 or Figure 4 or Figure 5 Schematic diagram of the required LED epitaxial wafer structure.

[0038] Figure 7 In the method of the present invention, Figure 6 After the current spreading layer is epitaxially grown, the product shown is made into a Figure 2 or Figure 3 or Figure 4 or Figure 5 Schematic diagram of the epitaxial wafer structure of the LED table shown.

[0039] Figure 8 In the method of the present invention, Figure 7 The product shown in the figure epitaxially grows an insulating material on the upper surface of the electron transport layer in the LED table, the side wall of the LED table and the edge of the upper surface of the current spreading layer, and obtains a Figure 2 Schematic diagram of the epitaxial wafer structure of the insulating layer shown.

[0040] Fig. 9 In the method of the present invention, Figure 8The product shown in the figure is made of anode electrodes on the insulating layer and current spreading layer through photolithography and evaporation technology, and the Figure 2 Schematic diagram of the sidewall field plate structure shown.

[0041] Fig.10 In the method of the present invention, Figure 7 The cathode electrode is made on the upper surface of the electron transport layer in the LED table by photolithography and evaporation technology, and the product has Figure 4 Schematic diagram of the epitaxial wafer structure of the cathode electrode shown.

[0042] Fig.11 In the method of the present invention, Fig.10 The product shown has epitaxially grown insulating materials on the upper surface of the electron transport layer in the LED table, the upper surface of the cathode electrode, the side wall of the LED table, and the edge of the upper surface of the current spreading layer, and has obtained a Figure 4 Schematic diagram of the epitaxial wafer structure of the insulating layer shown.

[0043] Fig.12 (a) is a comparison diagram of the electric field intensity at the left edge of the LED mesa of the light-emitting diode with sidewall field plates in Example 1 and the standard light-emitting diode; Fig.12 (b) is a comparison diagram of the electric field intensity at the right edge of the LED mesa of the light-emitting diode with sidewall field plates in Example 1 and the standard light-emitting diode.

[0044] Fig.13 (a) is a comparison diagram of the lateral hole concentration at the left edge of the LED mesa of the light-emitting diode with sidewall field plates in Example 1 and the standard light-emitting diode; Fig.13 (b) is a comparison diagram of the lateral hole concentration at the right edge of the LED mesa of the light-emitting diode with sidewall field plates in Example 1 and the standard light-emitting diode.

[0045] Among them, 101. substrate, 102. buffer layer, 103. electron transport layer, 104. active region layer, 105. electron blocking layer, 106. hole transport layer, 107. current spreading layer, 108. cathode electrode, 109. insulating layer, 110. anode electrode covering the current spreading layer, 111. anode electrode covering the insulating layer, H1. height of the insulating layer covering the upper surface of the electron transport layer, H2. height of the insulating layer covering the side wall from the electron blocking layer to the current spreading layer, H3. height of the insulating layer covering the edge of the upper surface of the current spreading layer, H4. height of the insulating layer covering the upper surface of the cathode electrode, W1. width of the insulating layer covering the upper surface of the electron transport layer, W2. width of the insulating layer covering the side wall from the electron blocking layer to the current spreading layer, W3. width of the insulating layer covering the edge of the upper surface of the current spreading layer, W4. width of the insulating layer covering the upper surface of the cathode electrode. DETAILED DESCRIPTION

[0046] Several light emitting diode device structures with sidewall field plates provided by the present invention are further described below in conjunction with the embodiments and drawings, but this is not intended to limit the protection scope of the claims of the present application.

[0047] A light emitting diode device structure with sidewall field plates (see Figure 2 ), an insulating layer 109 is covered on the upper surface of the electron transport layer 103 and the side walls of the electron blocking layer 105, the hole transport layer 106 and the current spreading layer 107 in the light-emitting diode table, and an anode electrode 111 covered on the insulating layer is prepared on the insulating layer 109; the sidewall field plate structure formed by the insulating layer 109 / anode electrode 111 covered on the insulating layer stacking structure provides a strong edge electric field for the light-emitting diode device, thereby depleting the higher carrier concentration at the edge of the device and reducing the defect recombination generated by the carriers.

[0048] In the sidewall field plate structure, the height H1 of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer 103 and the upper surface of the active region layer 104, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 0.001 to 500 μm; the height H2 of the insulating layer covering the side wall from the electron blocking layer to the current extension layer is the height of the side wall from the electron blocking layer 105 to the current extension layer 107, and the width W2 of the insulating layer covering the side wall from the electron blocking layer to the current extension layer is 0.001 to 1 μm, wherein W2 <W1。

[0049] Another light emitting diode device structure with sidewall field plates of the present invention (see Figure 3 ), an insulating layer 109 is covered on the upper surface of the electron transport layer 103, the electron blocking layer 105, the hole transport layer 106 and the side walls of the current spreading layer 107 in the light-emitting diode table, and an anode electrode 111 covered on the insulating layer is prepared on the insulating layer 109; a sidewall field plate structure formed by the insulating layer 109 / anode electrode 111 covered on the insulating layer stacking structure provides a strong edge electric field for the light-emitting diode device, thereby depleting the higher carrier concentration at the edge of the device and reducing the defect recombination generated by the carriers.

[0050] In the sidewall field plate structure described above, the height H1 of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer 103 and the upper surface of the active region layer 104, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 0.001 to 500 μm; the height H2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is the sidewall height from the electron blocking layer 105 to the current spreading layer 107, and the width W2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is 0.001 to 1 μm, where W2 < W1; the height H3 of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 to 1 μm, and the width W3 of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 to 200 μm.

[0051] Another light-emitting diode device structure with sidewall field plates according to the present invention (see Figure 4 ), an insulating layer 109 is covered on the upper surface of the electron transport layer 103, the electron blocking layer 105, the hole transport layer 106, the sidewalls of the current spreading layer 107, and the upper surface of the cathode electrode 108 in the light-emitting diode mesa, and an anode electrode 111 covering the insulating layer is fabricated on the insulating layer 109; the sidewall field plate structure formed by the insulating layer 109 / anode electrode 111 covering the insulating layer provides a strong edge electric field for the light-emitting diode device, thereby depleting the high carrier concentration at the edge of the device and reducing the defect recombination generated by carriers.

[0052] In the sidewall field plate structure described above, the height H1 of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer 103 and the upper surface of the active region layer 104, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 0.001 to 500 μm; the height H2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is the sidewall height from the electron blocking layer 105 to the current spreading layer 107, and the width W2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is 0.001 to 1 μm, where W2 < W1; the height H4 of the insulating layer covering the upper surface of the cathode electrode is the distance between the upper surface of the cathode electrode 108 and the upper surface of the active region layer 104, and the width W4 of the insulating layer covering the upper surface of the cathode electrode is 0.1% to 90% of the width of the cathode electrode 108.

[0053] Another light-emitting diode device structure with sidewall field plates according to the present invention (see Figure 5), an insulating layer 109 is covered on the upper surface of the electron transport layer 103, the sidewalls of the electron blocking layer 105, the hole transport layer 106 and the current spreading layer 107, the edge of the upper surface of the current spreading layer 107, and the upper surface of the cathode electrode 108, and an anode electrode 111 covering the insulating layer is fabricated on the insulating layer 109; the sidewall field plate structure formed by the insulating layer 109 / the anode electrode 111 covering the insulating layer provides a strong edge electric field for the light-emitting diode device, thereby depleting the high carrier concentration at the edge of the device and reducing the defect recombination generated by the carriers.

[0054] In the sidewall field plate structure, the height H1 of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer 103 and the upper surface of the active region layer 104, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 0.001 - 500 μm; the height H2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is the sidewall height from the electron blocking layer 105 to the current spreading layer 107, and the width W2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is 0.001 - 1 μm, where W2 < W1; the height H3 of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 - 1 μm, and the width W3 of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 - 200 μm; the height H4 of the insulating layer covering the upper surface of the cathode electrode is the distance between the upper surface of the cathode electrode 108 and the upper surface of the active region layer 104, and the width W4 of the insulating layer covering the upper surface of the cathode electrode is 0.1% - 90% of the width of the cathode electrode 108.

[0055] The material used for the insulating layer 109 in the sidewall field plate structure is undoped SiO2, Al2O3, Si3N4, HfO2, Ta2O5, AlN, LiF, diamond, PMMA, etc.

[0056] The material of the anode electrode 111 covering the insulating layer in the sidewall field plate structure is the same as that of the anode electrode 110 covering the current spreading layer in the standard light-emitting diode, and the materials are all Au, ITO, Ni / Au, Cr / Au, Pt / Au, Ni / Al, etc.

[0057] The coverage of the anode electrode 111 covered on the insulating layer in the sidewall field plate structure does not include the side walls of the insulating layer 109 prepared on the upper surface of the electron transport layer 103 and the upper surface of the cathode electrode 108; the anode electrode 111 covered on the insulating layer and the anode electrode 110 covered on the current spreading layer in a standard light-emitting diode can be connected to form one anode electrode or separated into two independent anode electrodes; the thickness of the anode electrode 111 covered on the insulating layer is the same as the thickness of the anode electrode 110 covered on the current spreading layer in a standard light-emitting diode.

[0058] The light emitting diode mesa is any one of the standard light emitting diodes, and the size of the light emitting diode mesa is 1 to 1000 μm;

[0059] The structure of the standard light emitting diode mainly includes a substrate 101, a buffer layer 102, an electron transport layer 103, an active region layer 104, an electron blocking layer 105, a hole transport layer 106, a current spreading layer 107, a cathode electrode 108 and an anode electrode 110 covering the current spreading layer. (See Figure 1 )

[0060] The active region layer 104 includes but is not limited to a multi-quantum well structure, a quantum dot layer, a perovskite layer or an organic layer, and its material includes but is not limited to GaN, AlGaN, InGaN, AlInGaN, GaAs, AlGaAs or AlGaInP.

[0061] The cathode electrode 108 is made of Ag, LiF, MgO, Al / Au, Cr / Au or Ti / Al / Ti / Au, etc., and covers the upper surface of the electron transport layer 103 .

[0062] The method for preparing a light-emitting diode device in which the upper surface of the electron transport layer 103 and the side walls of the electron blocking layer 105, the hole transport layer 106 and the current spreading layer 107 in the light-emitting diode mesa are provided with a sidewall field plate structure comprises the following steps:

[0063] 1) epitaxially growing a buffer layer 102, an electron transport layer 103, an active region layer 104, an electron blocking layer 105, a hole transport layer 106 and a current spreading layer 107 on the surface of a substrate 101 in sequence by using light emitting diode epitaxial growth techniques such as evaporation, deposition or liquid phase spin coating, so as to obtain an epitaxial layer structure of a light emitting diode;

[0064] 2) etching the epitaxial layer structure to the electron transport layer 103 by photolithography and dry etching process to form a light-emitting diode mesa;

[0065] 3) Depositing or spin coating an insulating layer 109 on the obtained light emitting diode mesa by evaporation, deposition or liquid phase spin coating;

[0066] 4) The insulating layer 109 is patterned by photolithography and wet etching techniques to form the insulating layer pattern in the sidewall field plate structure. The height H1 of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer 103 and the upper surface of the active region layer 104, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 0.001 - 500 μm; the height H2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is the sidewall height from the electron blocking layer 105 to the current spreading layer 107, and the width W2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is 0.001 - 1 μm, where W2 < W1;

[0067] 5) Photolithography and evaporation are performed to fabricate the anode electrode 110 covering the current spreading layer and the anode electrode 111 covering the insulating layer;

[0068] 6) Photolithography and evaporation are performed to fabricate the cathode electrode 108 covering the electron transport layer 103.

[0069] The preparation method of the light - emitting diode device with a sidewall field plate structure provided on the upper surface of the electron transport layer 103, the electron blocking layer 105, the sidewalls of the hole transport layer 106 and the current spreading layer 107, and the upper surface edge of the current spreading layer 107 in the light - emitting diode mesa is basically the same as the above steps. The difference is that in step 4), the insulating layer pattern in the sidewall field plate structure is fabricated by photolithography and wet etching techniques. The height H1 of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer 103 and the upper surface of the active region layer 104, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 0.001 - 500 μm; the height H2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is the sidewall height from the electron blocking layer 105 to the current spreading layer 107, and the width W2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is 0.001 - 1 μm, where W2 < W1; the height H3 of the insulating layer covering the upper surface edge of the current spreading layer is 0.001 - 1 μm, and the width W3 of the insulating layer covering the upper surface edge of the current spreading layer is 0.001 - 200 μm.

[0070] The preparation method of the light - emitting diode device with a sidewall field plate structure provided on the upper surface of the electron transport layer 103, the electron blocking layer 105, the sidewalls of the hole transport layer 106 and the current spreading layer 107, and the upper surface of the cathode electrode 108 includes the following steps:

[0071] 1) Using light-emitting diode epitaxial technologies such as evaporation, deposition, or liquid-phase spin coating, successively grow an epitaxial buffer layer 102, an electron transport layer 103, an active region layer 104, an electron blocking layer 105, a hole transport layer 106, and a current spreading layer 107 on the surface of a substrate 101 to obtain an epitaxial layer structure of the light-emitting diode;

[0072] 2) Etch the epitaxial layer structure by photolithography and dry etching processes to the electron transport layer 103 to fabricate a light-emitting diode mesa;

[0073] 3) Fabricate a cathode electrode 108 covering the electron transport layer 103 by photolithography and evaporation;

[0074] 4) Deposit or spin coat an insulating layer 109 on the obtained light-emitting diode mesa covered with the cathode electrode 108 by evaporation, deposition, or liquid-phase spin coating;

[0075] 5) Use photolithography and wet etching technologies to fabricate an insulating layer pattern in the sidewall field plate structure for the insulating layer 109. In this pattern, the height H1 of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer 103 and the upper surface of the active region layer 104, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 0.001 - 500 μm; the height H2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is the sidewall height from the electron blocking layer 105 to the current spreading layer 107, and the width W2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is 0.001 - 1 μm, where W2 < W1; the height H4 of the insulating layer covering the upper surface of the cathode electrode is the distance between the upper surface of the cathode electrode 108 and the upper surface of the active region layer 104, and the width W4 of the insulating layer covering the upper surface of the cathode electrode is 0.1% - 90% of the width of the cathode electrode 108;

[0076] 6) Fabricate an anode electrode 110 covering the current spreading layer and an anode electrode 111 covering the insulating layer by photolithography and evaporation.

[0077] A method for manufacturing a light-emitting diode device with a sidewall field plate structure disposed on the upper surface of an electron transport layer 103, the sidewalls of an electron blocking layer 105, a hole transport layer 106, and a current spreading layer 107, the edge of the upper surface of the current spreading layer 107, and the upper surface of a cathode electrode 108 in a light-emitting diode mesa. The steps are basically the same as the above steps, except that in step 5), an insulating layer pattern in the sidewall field plate structure is fabricated through photolithography and wet etching techniques. The height H1 of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer 103 and the upper surface of the active region layer 104. The width W1 of the insulating layer covering the upper surface of the electron transport layer is 0.001 - 500 μm. The height H2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is the sidewall height from the electron blocking layer 105 to the current spreading layer 107. The width W2 of the insulating layer covering the sidewalls from the electron blocking layer to the current spreading layer is 0.001 - 1 μm, where W2 < W1. The height H3 of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 - 1 μm. The width W3 of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 - 200 μm. The height H4 of the insulating layer covering the upper surface of the cathode electrode is the distance between the upper surface of the cathode electrode 108 and the upper surface of the active region layer 104. The width W4 of the insulating layer covering the upper surface of the cathode electrode is 0.1% - 90% of the width of the cathode electrode 108.

[0078] For the light-emitting diode device structure with a sidewall field plate, the raw materials involved can be obtained through general channels, and the operating processes in its manufacturing method are possessed by those skilled in the art.

[0079] In the present invention, the light-emitting diode device structure with a sidewall field plate巧妙combines the sidewall field plate structure with a standard light-emitting diode device. Therefore, the following three embodiments are mainly designed and verified for devices with different sidewall field plate structures. What is not described in the present invention is applicable to the prior art.

[0080] Embodiment 1

[0081] For the light-emitting diode device structure with a sidewall field plate and its manufacturing method described in this embodiment, reference can be made to Figure 2 、 Figure 6 、 Figure 7 、 Figure 8 、 Fig. 9 、 Fig.12 and Fig.13 :

[0082] Figure 2 It should be noted that the Chinese character "巧妙" in the original text is translated as "巧妙" in the English text for the time being. You can provide a more accurate English expression according to the actual situation.The illustrated embodiment shows that the light-emitting diode device structure of the present invention has a sidewall field plate, and its structure includes: a substrate 101, a buffer layer 102, an electron transport layer 103, an active region layer 104, an electron blocking layer 105, a hole transport layer 106, a current spreading layer 107, a cathode electrode 108, an insulating layer 109, an anode electrode 110 covering the current spreading layer, and an anode electrode 111 covering the insulating layer.

[0083] Figure 6 The structure shown shows that in this embodiment, an LED epitaxial wafer structure schematic diagram is produced by epitaxial technology on a substrate 101. The structure includes: a substrate 101, a buffer layer 102, an electron transport layer 103, an active region layer 104, an electron blocking layer 105, a hole transport layer 106 and a current spreading layer 107.

[0084] Figure 7 The structure shown in the figure shows that in this embodiment, after the current spreading layer 107 is epitaxially grown, the epitaxial wafer structure of the light-emitting diode table is manufactured by photolithography and dry etching processes. The structure includes: substrate 101, buffer layer 102, electron transport layer 103, active region layer 104, electron blocking layer 105, hole transport layer 106 and current spreading layer 107.

[0085] Figure 8 The structure shown shows that in this embodiment, a schematic diagram of the epitaxial structure of a light-emitting diode table covered with an insulating layer 109 is produced by photolithography and wet etching technology, and its structure includes: a substrate 101, a buffer layer 102, an electron transport layer 103, an active area layer 104, an electron blocking layer 105, a hole transport layer 106, a current spreading layer 107 and an insulating layer 109.

[0086] Fig. 9 The structure shown shows that, in this embodiment, an anode electrode 110 covering the current spreading layer and an anode electrode 111 covering the insulating layer are respectively manufactured on the current spreading layer 107 and the insulating layer 109 by photolithography technology and evaporation technology, thereby obtaining a schematic diagram of a device structure with a sidewall field plate structure, the structure of which includes: a substrate 101, a buffer layer 102, an electron transport layer 103, an active region layer 104, an electron blocking layer 105, a hole transport layer 106, a current spreading layer 107, an insulating layer 109, an anode electrode 110 covering the current spreading layer, and an anode electrode 111 covering the insulating layer.

[0087] Fig.12 (a) and Fig.12 The curve (b) shows that the electric field intensity at the left and right edges of the LED mesa of the LED with sidewall field plates represented by the dotted line in this embodiment is increased by 37.5% compared with the electric field intensity at the left and right edges of the standard LED mesa.

[0088] Fig.13 (a) and Fig.13 The curve shown in (b) shows that in this embodiment, compared with the standard light-emitting diode, the hole concentration at the left and right sidewall edges of the light-emitting diode with sidewall field plates is reduced by 26.4%.

[0089] The size of the light emitting diode device structure with the sidewall field plate is 20 μm×20 μm.

[0090] The substrate 101 is made of sapphire; the material of the buffer layer 102 is AlN; the material of the electron transport layer 103 is Al 0.60 Ga 0.40 N; the active region layer 104 is a multi-quantum well structure, which is 5 periods of Al 0.45 Ga 0.55 N / A 0.57 Ga 0.43 N stacked layer; the material of the electron blocking layer 105 is Al 0.60 Ga 0.40 N; the material of the hole transport layer 106 is Al 0.40 Ga 0.60 N / GaN; the material of the current spreading layer 107 is Ni / Au.

[0091] The material used for the insulating layer 109 in the side wall field plate structure is Ta2O5.

[0092] A portion of the insulating layer 109 in the sidewall field plate structure covers the upper surface of the electron transport layer 103 in the light-emitting diode table, the height H1 of the insulating layer covering the upper surface of the electron transport layer is 0.58μm, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 1μm; a portion of the insulating layer covers the side walls from the electron blocking layer 105 to the current expansion layer 107 in the light-emitting diode table, the height H2 of the insulating layer covering the side walls from the electron blocking layer to the current expansion layer is 0.15μm, and the width W2 of the insulating layer covering the side walls from the electron blocking layer to the current expansion layer is 0.001μm.

[0093] The anode electrode 110 covered on the current spreading layer and the anode electrode 111 covered on the insulating layer are both made of Al / Ti / Au.

[0094] The cathode electrode 108 is made of Cr / Al / Ti / Au.

[0095] The above-mentioned light-emitting diode device epitaxial structure with a field plate structure is prepared by the following method:

[0096] 1) In an MOCVD reactor, a buffer layer 102 is epitaxially grown on the surface of a substrate 101 at a growth temperature of 1050° C. and a gas pressure of 50 mbar, thereby filtering dislocation defects and releasing stress caused by lattice mismatch; an electron transport layer 103 is epitaxially grown at a growth temperature of 1050° C. and a gas pressure of 50 mbar; then a multi-quantum well structure of 5 periods is epitaxially grown as an active region 104 at a growth temperature of 1000° C. and a gas pressure of 80 mbar; then an electron blocking layer 105 is epitaxially grown at a growth temperature of 1020° C. and a gas pressure of 80 mbar; and a hole transport layer 106 is continuously grown at a growth temperature of 1000° C. and a gas pressure of 50 mbar; finally, a current spreading layer 107 is epitaxially grown; (for this process, see Figure 6 )

[0097] 2) Etching the epitaxial layer structure to the electron transport layer 103 by photolithography and dry etching process to form a light-emitting diode table; (For this process, see Figure 7 )

[0098] 3) depositing an insulating layer 109 on the obtained light-emitting diode mesa by deposition or evaporation, wherein the material of the insulating layer 109 is non-doped Ta2O5;

[0099] 4) The Ta2O5 insulating layer 109 is etched by photolithography and wet etching technology. A portion of the insulating layer 109 obtained after etching covers the upper surface of the electron transport layer 103 in the light-emitting diode mesa. The height H1 of the insulating layer covering the upper surface of the electron transport layer is 0.58 μm, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 1 μm; a portion of the insulating layer covers the side wall from the electron blocking layer 105 to the current spreading layer 107 in the light-emitting diode mesa. The height H2 of the insulating layer covering the side wall is 0.15 μm, and the width W2 of the insulating layer covering the side wall is 0.001 μm; (For this process, see Figure 8 )

[0100] 5) The anode electrode 110 covering the current spreading layer and the anode electrode 111 covering the insulating layer are manufactured by photolithography and evaporation; (For this process, see Fig. 9 )

[0101] 6) A cathode electrode 108 covering the electron transport layer 103 is produced by photolithography and evaporation (see Figure 2 ).

[0102] Thus, the light emitting diode device structure with sidewall field plates of the present invention is obtained. Fig.12 (a) and Fig.12As shown in (b), due to the use of the sidewall field plate structure in this embodiment, the electric field strength at the left and right sidewall edges of the LED table of the light-emitting diode with sidewall field plates represented by the dotted line is increased by 37.5% compared with the electric field strength at the left and right sidewall edges of the standard light-emitting diode. Fig.13 (a) and Fig.13 The curve shown in (b) indicates that, due to the increase in the field strength at the sidewall edge of the light-emitting diode with the sidewall field plate in this embodiment, the hole concentration at the left and right sidewall edges of the light-emitting diode table is reduced by 26.4% compared with the standard light-emitting diode, thereby suppressing the non-radiative recombination at the edge of the LED table, thereby improving the luminous efficiency of the device by 9.5%.

[0103] Example 2

[0104] The light emitting diode device structure with sidewall field plates in this embodiment can be found in Figure 3 :

[0105] Figure 3 The illustrated embodiment shows that the light-emitting diode device structure of the present invention has a sidewall field plate, and its structure includes: a substrate 101, a buffer layer 102, an electron transport layer 103, an active region layer 104, an electron blocking layer 105, a hole transport layer 106, a current spreading layer 107, a cathode electrode 108, an insulating layer 109, an anode electrode 110 covering the current spreading layer, and an anode electrode 111 covering the insulating layer.

[0106] The difference between this embodiment and Embodiment 1 is that the material used for the insulating layer 109 in the sidewall field plate structure in this embodiment is SiO 2 .

[0107] A portion of the insulating layer 109 in the sidewall field plate structure covers the upper surface of the electron transport layer 103 in the light-emitting diode mesas, the height H1 of the insulating layer covering the upper surface of the electron transport layer is 0.58 μm, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 5 μm; a portion of the insulating layer 109 covers the side walls from the electron blocking layer 105 to the current spreading layer 107 in the light-emitting diode mesas, the height H2 of the insulating layer covering the side walls from the electron blocking layer to the current spreading layer is 0.15 μm, and the width W2 of the insulating layer covering the side walls from the electron blocking layer to the current spreading layer is 0.01 μm; a portion of the insulating layer 109 covers the edge of the upper surface of the current spreading layer 107, the height H3 of the insulating layer covering the edge of the upper surface of the current spreading layer is 50 μm, and the width W3 of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.01 μm.

[0108] The anode electrode 110 covered on the current spreading layer and the anode electrode 111 covered on the insulating layer are made of Ni / Au.

[0109] The cathode electrode 108 is made of Ti / Al / Ti / Au.

[0110] The above-mentioned light-emitting diode device epitaxial structure with a field plate structure is prepared by the following method:

[0111] 1) In an MOCVD reactor, epitaxially grow a buffer layer 102 on the surface of a substrate 101 at a growth temperature of 1050° C. and a gas pressure of 50 mbar, thereby filtering dislocation defects and releasing stress caused by lattice mismatch; continue to epitaxially grow an electron transport layer 103 at a growth temperature of 1050° C. and a gas pressure of 50 mbar; then epitaxially grow a multi-quantum well structure of 5 periods as an active region 104 at a growth temperature of 1000° C. and a gas pressure of 80 mbar; then epitaxially grow an electron blocking layer 105 at a growth temperature of 1020° C. and a gas pressure of 80 mbar; and continue to grow a hole transport layer 106 at a growth temperature of 1000° C. and a gas pressure of 50 mbar; finally, epitaxially grow a current spreading layer 107;

[0112] 2) etching the epitaxial layer structure to the electron transport layer 103 by photolithography and dry etching process to form a light-emitting diode mesa;

[0113] 3) depositing an insulating layer 109 on the obtained light-emitting diode mesa by deposition or evaporation, wherein the material of the insulating layer 109 is non-doped SiO2;

[0114] 4) The SiO2 insulating layer 109 is etched by photolithography and wet etching techniques, and a portion of the insulating layer 109 obtained after etching covers the upper surface of the electron transport layer 103 in the light-emitting diode mesas, and the height H1 of the insulating layer covering the upper surface of the electron transport layer is 0.58 μm, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 5 μm; a portion of the insulating layer 109 covers the side wall from the electron blocking layer 105 to the current expansion layer 107 in the light-emitting diode mesas, and the height H2 of the insulating layer covering the side wall from the electron blocking layer to the current expansion layer is 0.15 μm, and the width W2 of the insulating layer covering the side wall from the electron blocking layer to the current expansion layer is 0.01 μm; a portion of the insulating layer 109 covers the edge of the upper surface of the current expansion layer 107, and the height H3 of the insulating layer covering the edge of the upper surface of the current expansion layer is 50 μm, and the width W3 of the insulating layer covering the edge of the upper surface of the current expansion layer is 0.01 μm;

[0115] 5) The anode electrode 110 covering the current spreading layer and the anode electrode 111 covering the insulating layer are manufactured by photolithography and evaporation;

[0116] 6) A cathode electrode 108 covering the electron transport layer 103 is manufactured by photolithography and evaporation.

[0117] Thus, the light emitting diode device with sidewall field plates of the present invention is obtained. The electric field strength of the left and right sidewall edges of the light emitting diode device with sidewall field plates in this embodiment is enhanced by 21%, and the hole concentration at the edge of the device is reduced by 15.2%, thereby inhibiting the non-radiative recombination at the edge of the LED table, and improving the luminous efficiency of the device by 6%.

[0118] Example 3

[0119] The light emitting diode device structure with sidewall field plates and the preparation method thereof in this embodiment can be found in Figure 4 , Figure 6 , Figure 7 , Fig.10 and Fig.11 :

[0120] Figure 4 The illustrated embodiment shows that the light-emitting diode device structure of the present invention has a sidewall field plate, and its structure includes: a substrate 101, a buffer layer 102, an electron transport layer 103, an active region layer 104, an electron blocking layer 105, a hole transport layer 106, a current spreading layer 107, a cathode electrode 108, an insulating layer 109, an anode electrode 110 covering the current spreading layer, and an anode electrode 111 covering the insulating layer.

[0121] Figure 6 The structure shown shows that in this embodiment, a structural schematic diagram of an LED epitaxial wafer is produced on a substrate 101 by epitaxial technology, and its structure includes: a substrate 101, a buffer layer 102, an electron transport layer 103, an active area layer 104, an electron blocking layer 105, a hole transport layer 106 and a current expansion layer 107.

[0122] Figure 7 The structure shown shows that in this embodiment, after the current spreading layer 107 is epitaxially grown, a schematic diagram of the epitaxial wafer structure of the light-emitting diode table is produced by photolithography and dry etching processes, and its structure includes: a substrate 101, a buffer layer 102, an electron transport layer 103, an active area layer 104, an electron blocking layer 105, a hole transport layer 106 and a current spreading layer 107.

[0123] Fig.10 The illustrated embodiment shows that, in this embodiment, a cathode electrode 108 is produced on the upper surface of the electron transport layer 103 of the light-emitting diode table by photolithography and evaporation technology, and a schematic diagram of the epitaxial wafer structure of the light-emitting diode table with the cathode electrode 108 is obtained, and its structure includes: a substrate 101, a buffer layer 102, an electron transport layer 103, an active area layer 104, an electron blocking layer 105, a hole transport layer 106, a current spreading layer 107 and a cathode electrode 108.

[0124] Fig.11The illustrated embodiment shows that in this embodiment, a schematic diagram of the epitaxial structure of a light-emitting diode covered with an insulating layer 109 is produced by photolithography and wet etching techniques, and its structure includes: a substrate 101, a buffer layer 102, an electron transport layer 103, an active region layer 104, an electron blocking layer 105, a hole transport layer 106, a current spreading layer 107, a cathode electrode 108 and an insulating layer 109.

[0125] The size of the light emitting diode device with the sidewall field plate is 500 μm×500 μm.

[0126] The material used for the insulating layer 109 in the side wall field plate structure is Al2O3.

[0127] A portion of the insulating layer 109 in the sidewall field plate structure covers the upper surface of the electron transport layer 103 in the light-emitting diode mesas, the height H1 of the insulating layer covering the upper surface of the electron transport layer is 0.58 μm, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 50 μm; a portion of the insulating layer 109 covers the side walls from the electron blocking layer 105 to the current expansion layer 107 in the light-emitting diode mesas, the height H2 of the insulating layer covering the side walls from the electron blocking layer to the current expansion layer is 0.15 μm, and the width W2 of the insulating layer covering the side walls from the electron blocking layer to the current expansion layer is 0.5 μm; a portion of the insulating layer 109 covers the upper surface of the cathode electrode 108, the height H4 of the insulating layer covering the upper surface of the cathode electrode is 0.21 μm, and the width W4 of the insulating layer covering the upper surface of the cathode electrode is 25% of the width of the cathode electrode 108.

[0128] The anode electrode 110 covered on the current spreading layer and the anode electrode 111 covered on the insulating layer are made of Cr / Au.

[0129] The cathode electrode 108 is made of Cr / Au.

[0130] The above-mentioned light-emitting diode device epitaxial structure with a field plate structure is prepared by the following method:

[0131] 1) In an MOCVD reactor, a buffer layer 102 is epitaxially grown on the surface of a substrate 101 at a growth temperature of 1050° C. and a gas pressure of 50 mbar, thereby filtering dislocation defects and releasing stress caused by lattice mismatch; an electron transport layer 103 is epitaxially grown at a growth temperature of 1050° C. and a gas pressure of 50 mbar; then a multi-quantum well structure of 5 periods is epitaxially grown as an active region 104 at a growth temperature of 1000° C. and a gas pressure of 80 mbar; then an electron blocking layer 105 is epitaxially grown at a growth temperature of 1020° C. and a gas pressure of 80 mbar; and a hole transport layer 106 is continuously grown at a growth temperature of 1000° C. and a gas pressure of 50 mbar; finally, a current spreading layer 107 is epitaxially grown; (for this process, see Figure 6 )

[0132] 2) Etching the epitaxial layer structure to the electron transport layer 103 by photolithography and dry etching process to form a light-emitting diode table; (For this process, see Figure 7 )

[0133] 3) A cathode electrode 108 covering the electron transport layer 103 is produced by photolithography and evaporation; (For this process, see Fig.10 )

[0134] 4) Depositing an insulating layer 109 on the obtained LED table top covered with the cathode electrode 108 by deposition or evaporation, wherein the material used for the insulating layer 109 is non-doped Al2O3;

[0135] 5) The Al2O3 insulating layer 109 is etched by photolithography and wet etching techniques. In the etched pattern, a portion of the insulating layer 109 covers the upper surface of the electron transport layer 103 in the light-emitting diode mesas, the height H1 of the insulating layer covering the upper surface of the electron transport layer is 0.58 μm, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 50 μm; a portion of the insulating layer 109 covers the side wall from the electron blocking layer 105 to the current expansion layer 107 in the light-emitting diode mesas, the height H2 of the insulating layer covering the side wall from the electron blocking layer to the current expansion layer is 0.15 μm, and the width W2 of the insulating layer covering the side wall from the electron blocking layer to the current expansion layer is 0.5 μm; a portion of the insulating layer 109 covers the upper surface of the cathode electrode 108, the height H4 of the insulating layer covering the upper surface of the cathode electrode is 0.21 μm, and the width W4 of the insulating layer covering the upper surface of the cathode electrode is 25% of the width of the cathode electrode 108; (For this process, see Fig.11 )

[0136] 6) The anode electrode 110 covering the current spreading layer and the anode electrode 111 covering the insulating layer 109 are manufactured by photolithography and evaporation. (For this process, see Figure 4 )

[0137] Thus, the light emitting diode device with sidewall field plates of the present invention is obtained. The electric field strength of the light emitting diode device with sidewall field plates in this embodiment is increased by 25% at the left and right sidewall edges of the device, and the hole concentration at the edge of the device is reduced by 18.5%, thereby inhibiting the non-radiative recombination at the edge of the LED table, and improving the luminous efficiency of the device by 8%.

[0138] Example 4

[0139] The light emitting diode device structure with sidewall field plates and the preparation method thereof in this embodiment can be found in Figure 5 :

[0140] Figure 5 The illustrated embodiment shows that the light-emitting diode device structure of the present invention has a sidewall field plate, and its structure includes: a substrate 101, a buffer layer 102, an electron transport layer 103, an active region layer 104, an electron blocking layer 105, a hole transport layer 106, a current spreading layer 107, a cathode electrode 108, an insulating layer 109, an anode electrode 110 covering the current spreading layer, and an anode electrode 111 covering the insulating layer.

[0141] The difference between this embodiment and embodiment 3 is that the size of the light emitting diode device with sidewall field plates in this embodiment is 1000 μm×1000 μm.

[0142] The material used for the insulating layer 109 in the side wall field plate structure is Al2O3.

[0143] A portion of the insulating layer 109 in the sidewall field plate structure covers the upper surface of the electron transport layer 103 in the light-emitting diode mesa, the height H1 of the insulating layer covering the upper surface of the electron transport layer is 0.58 μm, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 100 μm; a portion of the insulating layer 109 covers the side wall from the electron blocking layer 105 to the current expansion layer 107 in the light-emitting diode mesa, the height H2 of the insulating layer covering the side wall from the electron blocking layer to the current expansion layer is 0.15 μm, and the width W1 of the insulating layer covering the side wall from the electron blocking layer to the current expansion layer is 100 μm. The width W2 of the insulating layer on the side wall of the expansion layer is 1μm; a portion of the insulating layer 109 covers the edge of the upper surface of the current expansion layer 107, the height H3 of the insulating layer covering the edge of the upper surface of the current expansion layer is 1μm, and the width W3 of the insulating layer covering the edge of the upper surface of the current expansion layer is 100μm; a portion of the insulating layer 109 covers the upper surface of the cathode electrode 108, the height H4 of the insulating layer covering the upper surface of the cathode electrode is 0.21μm, and the width W4 of the insulating layer covering the upper surface of the cathode electrode is 25% of the width of the cathode electrode 108.

[0144] The anode electrode 110 covered on the current spreading layer and the anode electrode 111 covered on the insulating layer are made of Cr / Au.

[0145] The cathode electrode 108 is made of Cr / Au.

[0146] The above-mentioned light-emitting diode device epitaxial structure with a field plate structure is prepared by the following method:

[0147] 1) In an MOCVD reactor, epitaxially grow a buffer layer 102 on the surface of a substrate 101 at a growth temperature of 1050° C. and a gas pressure of 50 mbar, thereby filtering dislocation defects and releasing stress caused by lattice mismatch; continue to epitaxially grow an electron transport layer 103 at a growth temperature of 1050° C. and a gas pressure of 50 mbar; then epitaxially grow a multi-quantum well structure of 5 periods as an active region 104 at a growth temperature of 1000° C. and a gas pressure of 80 mbar; then epitaxially grow an electron blocking layer 105 at a growth temperature of 1020° C. and a gas pressure of 80 mbar; and continue to grow a hole transport layer 106 at a growth temperature of 1000° C. and a gas pressure of 50 mbar; finally, epitaxially grow a current spreading layer 107;

[0148] 2) etching the epitaxial layer structure to the electron transport layer 103 by photolithography and dry etching process to form a light-emitting diode mesa;

[0149] 3) A cathode electrode 108 covering the electron transport layer 103 is manufactured by photolithography and evaporation;

[0150] 4) Depositing an insulating layer 109 on the obtained LED table top covered with the cathode electrode 108 by deposition or evaporation, wherein the material used for the insulating layer 109 is non-doped Al2O3;

[0151] 5) The Al2O3 insulating layer 109 is etched by photolithography and wet etching techniques. In the etched pattern, a portion of the insulating layer 109 covers the upper surface of the electron transport layer 103 in the light-emitting diode mesa, and the height H1 of the insulating layer covering the upper surface of the electron transport layer is 0.58 μm, and the width W1 of the insulating layer covering the upper surface of the electron transport layer is 100 μm; a portion of the insulating layer 109 covers the side wall from the electron blocking layer 105 to the current spreading layer 107 in the light-emitting diode mesa, and the height H2 of the insulating layer covering the side wall from the electron blocking layer to the current spreading layer is 0.15 μm. m, the width W2 of the insulating layer covering the side wall from the electron blocking layer to the current spreading layer is 1 μm; a portion of the insulating layer 109 covers the edge of the upper surface of the current spreading layer 107, the height H3 of the insulating layer covering the edge of the upper surface of the current spreading layer is 1 μm, and the width W3 of the insulating layer covering the edge of the upper surface of the current spreading layer is 100 μm; a portion of the insulating layer 109 covers the upper surface of the cathode electrode 108, the height H4 of the insulating layer covering the upper surface of the cathode electrode is 0.21 μm, and the width W4 of the insulating layer covering the upper surface of the cathode electrode is 25% of the width of the cathode electrode 108;

[0152] 6) The anode electrode 110 covering the current spreading layer and the anode electrode 111 covering the insulating layer are manufactured by photolithography and evaporation.

[0153] Thus, the light emitting diode device with sidewall field plates of the present invention is obtained. The electric field strength of the left and right sidewall edges of the light emitting diode device with sidewall field plates in this embodiment is enhanced by 17%, and the hole concentration at the edge of the device is reduced by 11.5%, thereby inhibiting the non-radiative recombination at the edge of the LED table, and improving the luminous efficiency of the device by 4%.

[0154] The raw materials involved in the above-mentioned light-emitting diode device with sidewall field plates can be obtained through general channels, and the operating processes in the preparation method are within the capabilities of those skilled in the art.

[0155] Combining the results obtained in various embodiments, we found that the change of the sidewall field plate structure at the edge of the LED table has a certain impact on the device performance, and as the dielectric constant of the insulating layer material in the sidewall field plate structure increases and the thickness decreases, the carrier depletion effect of the structure becomes stronger, while the leakage and non-radiative recombination losses at the edge of the device are weakened. In addition, the effect of the sidewall field plate structure will also be affected by the size of the LED. The specific material and thickness of the sidewall field plate structure need to be properly optimized according to different device structures and process methods, so that the sidewall field plate structure can achieve the best effect.

Claims

1. A light emitting diode device structure having a sidewall field plate, characterized in that The sidewall field plate structure is composed of an insulating layer (109) and an anode electrode (111) covering the insulating layer; the sidewall field plate structure is arranged on the upper surface of the electron transport layer (103) in the light-emitting diode table and the side wall from the electron blocking layer (105) to the current expansion layer (107); or the sidewall field plate structure is arranged on the upper surface of the electron transport layer (103) in the light-emitting diode table, the side wall from the electron blocking layer (105) to the current expansion layer (107) and the edge of the upper surface of the current expansion layer (107); the height (H1) of the insulating layer covering the upper surface of the electron transport layer in the sidewall field plate structure is the distance between the upper surface of the electron transport layer (103) and the upper surface of the active region layer (104), and the width (W1) of the insulating layer covering the upper surface of the electron transport layer is 0.001 to 500 μm; the height (H2) of the insulating layer covering the side wall from the electron blocking layer to the current spreading layer is the height of the side wall from the electron blocking layer (105) to the current spreading layer (107), and the width (W2) of the insulating layer covering the side wall from the electron blocking layer to the current spreading layer is 0.001 to 1 μm, wherein W2 <W1; The height (H3) of the insulating layer covering the edge of the upper surface of the current expansion layer is 0.001 to 1 μm, and the width (W3) of the insulating layer covering the edge of the upper surface of the current expansion layer is 0.001 to 200 μm; the side wall field plate structure covers part of the cathode electrode (108); the height (H4) of the insulating layer covering the upper surface of the cathode electrode in the side wall field plate structure is the distance between the upper surface of the cathode electrode (108) and the upper surface of the active region layer (104), and the width (W4) of the insulating layer covering the upper surface of the cathode electrode is 0.1% to 90% of the width of the upper surface of the cathode electrode (108).

2. The light emitting diode device structure with sidewall field plates according to claim 1, characterized in that The material used for the insulating layer (109) in the side wall field plate structure is non-doped SiO2, Al2O3, Si3N4, HfO2, Ta2O5, AlN, LiF, diamond or PMMA.

3. The light emitting diode device structure with sidewall field plates according to claim 1, characterized in that The material of the anode electrode (111) covered on the insulating layer in the side wall field plate structure is the same as the material of the anode electrode (110) covered on the current expansion layer in a standard light emitting diode, and the materials are Au, ITO, Ni / Au, Cr / Au, Pt / Au or Ni / Al.

4. The light-emitting diode device structure with sidewall field plates as claimed in claim 3, characterized in that the coverage of the anode electrode (111) covered on the insulating layer does not include the side walls of the insulating layer (109) prepared on the upper surface of the electron transport layer (103) and the upper surface of the cathode electrode (108); the anode electrode (111) covered on the insulating layer and the anode electrode (110) covered on the current spreading layer in a standard light-emitting diode are connected to form one anode electrode or separated into two independent anode electrodes; the thickness of the anode electrode (111) covered on the insulating layer is the same as the thickness of the anode electrode (110) covered on the current spreading layer in a standard light-emitting diode.

5. The light emitting diode device structure with sidewall field plates according to claim 1, characterized in that The light-emitting diode mesa is any one of standard light-emitting diodes, and the size of the light-emitting diode mesa is 1 to 1000 μm; the standard light-emitting diode device structure mainly includes a substrate (101), a buffer layer (102), an electron transport layer (103), an active region layer (104), an electron blocking layer (105), a hole transport layer (106), a current expansion layer (107), a cathode electrode (108), and an anode electrode (110) covering the current expansion layer; the active region layer (104) includes but is not limited to a multi-quantum well structure, a quantum dot layer, a perovskite layer, or an organic layer.

6. The method for preparing a light emitting diode device structure with a sidewall field plate according to claim 1, characterized in that The steps include: 1) epitaxially growing a buffer layer (102), an electron transport layer (103), an active region layer (104), an electron blocking layer (105), a hole transport layer (106) and a current spreading layer (107) on the surface of a substrate (101) in sequence by using a light emitting diode epitaxial growth technology such as evaporation, deposition or liquid phase spin coating, thereby obtaining an epitaxial layer structure of a light emitting diode; 2) etching the epitaxial layer structure to the electron transport layer (103) by photolithography and dry etching processes to form a light-emitting diode table; 3) Photolithography and evaporation to produce a cathode electrode (108) covering the electron transport layer (103); 4) depositing or spin coating an insulating layer (109) on a portion of the cathode electrode (108) and the light-emitting diode table by evaporation, deposition or liquid phase spin coating; 5) An insulating layer pattern in the side wall field plate structure is produced by photolithography and wet etching technology, wherein the height (H1) of the insulating layer covering the upper surface of the electron transport layer is the distance between the upper surface of the electron transport layer (103) and the upper surface of the active region layer (104), and the width (W1) of the insulating layer covering the upper surface of the electron transport layer is 0.001 to 500 μm; the height (H2) of the insulating layer covering the side wall from the electron blocking layer to the current spreading layer is the height of the side wall from the electron blocking layer (105) to the current spreading layer (107), and the width (W2) of the insulating layer covering the side wall from the electron blocking layer to the current spreading layer is 0.001 to 1 μm, wherein W2 <W1; The height (H3) of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 to 1 μm, and the width (W3) of the insulating layer covering the edge of the upper surface of the current spreading layer is 0.001 to 200 μm; the height (H4) of the insulating layer covering the upper surface of the cathode electrode is the distance between the upper surface of the cathode electrode (108) and the upper surface of the active region layer (104), and the width (W4) of the insulating layer covering the upper surface of the cathode electrode is 0.1% to 90% of the width of the upper surface of the cathode electrode (108); 6) Photolithography and evaporation are performed to produce an anode electrode (110) covering the current spreading layer and an anode electrode (111) covering the insulating layer.

Images