阅读说明：本技术 一种基于ain/pss复合衬底的高亮度发光二极管及其制备方法 (High-brightness light-emitting diode based on AIN/PSS composite substrate and preparation method thereof ) 是由 贾传宇 胡西多 于 2019-09-30 设计创作，主要内容包括：本发明公开了一种基于AIN/PSS复合衬底的高亮度发光二极管及其制备方法,所述高亮度发光二极管包括从下到上依次层叠设置的AlN/PSS复合衬底、u型GaN合并层、n型GaN层、低温GaN V-pits层、有源区、电子阻挡层、高温p型GaN层和接触层。本发明的高亮度发光二极管包括新型结构的u-GaN合并层,以及V-pits层和有源区,能够有效提高外延层晶体质量,有效缓解有源区应力,并改善水平方向电流扩展,进而实现提高发光二极管发光效率的目的,制得的发光二极管亮度高。(The invention discloses a high-brightness light-emitting diode based on an AIN/PSS composite substrate and a preparation method thereof. The high-brightness light-emitting diode comprises a u-GaN merging layer with a novel structure, a V-pits layer and an active region, can effectively improve the crystal quality of an epitaxial layer, effectively relieves the stress of the active region, improves the current expansion in the horizontal direction, further realizes the purpose of improving the light-emitting efficiency of the light-emitting diode, and is high in brightness.)

1. The high-brightness light-emitting diode based on the AIN/PSS composite substrate is characterized by comprising an AlN/PSS composite substrate (101), a u-type GaN merging layer (102), an n-type GaN layer (103), a low-temperature GaN V-pits layer (104), an active region (105), an electron blocking layer (106), a high-temperature p-type GaN layer (107) and a contact layer (108) which are sequentially stacked from bottom to top;

the u-shaped GaN merging layer (102) comprises a first u-shaped GaN layer, a second u-shaped GaN layer and a third u-shaped GaN layer which are sequentially stacked from bottom to top; the thickness of the first u-type GaN layer is 0.8-1 μm, the growth temperature is 1010-1020 ℃, the pressure of the reaction chamber is 200-300 torr, and the molar ratio of the group V source to the group III source is 1000-1200-; the thickness of the second u-type GaN layer is 0.8-1 mu m, the growth temperature is 1020-1030 ℃, the pressure of the reaction chamber is 100-150 torr, and the molar ratio of the group V source to the group III source is 1300-1500; the thickness of the third u-type GaN layer is 0.8-1 μm, the growth temperature is 1050-1080 ℃, the pressure of the reaction chamber is 75-100 torr, and the molar ratio of the group V source to the group III source is 1300-1500.

2. The high-brightness light-emitting diode (LED) of claim 1, wherein said low-temperature GaN V-pits layer (104) comprises a first u-GaN layer, an n-GaN layer and a second u-GaN layer sequentially stacked from bottom to top^--a GaN layer, a second u-GaN layer and n⁺-a GaN layer; wherein the thickness of the first u-GaN layer is 80-90 nm; n is^-The thickness of the GaN layer is 70-80 nm, and the doping concentration of Si is 5 multiplied by 10¹⁷～8×10¹⁷cm^-3(ii) a The thickness of the second u-GaN layer is 80-90 nm; n is⁺The thickness of the GaN layer is 90-100 nm, and the doping concentration of Si is 3 multiplied by 10¹⁸～8×10¹⁸cm^-3。

3. A high brightness led according to claim 2, wherein said active region (105) is a triple-graded InGaN/GaN superlattice structure, comprising a first gradient, a second gradient and a third gradient sequentially stacked from bottom to top; the first gradient is a u-shaped InGaN/GaN superlattice with a period of 10-20 cycles, the thickness of an InGaN well layer with the first gradient is 1-1.5 nm, and the thickness of a GaN barrier layer with the first gradient is 1.5-2 nm; the second gradient is 2-3 periods of n-type InGaN/GaN superlattice, the thickness of the InGaN well layer of the second gradient is 2.5-3 nm, the thickness of the GaN barrier layer of the second gradient is 3-5 nm, and the Si doping concentration is 2 multiplied by 10¹⁸～3×10¹⁸cm^-3(ii) a The third gradient is a 4-6 period u-shaped InGaN/GaN superlattice, and the thickness of a InGaN well layer of the third gradientThe thickness of the GaN barrier layer with the third gradient is 2.5-3.5 nm, and the thickness of the GaN barrier layer with the third gradient is 5-6.5 nm.

4. A high brightness LED according to claim 3, wherein said electron blocking layer (106) is p-type Al with 5-10 periods_yGa_1-yN/GaN, wherein Al_yGa_1-yThe thickness of N is 1-2 nm, and the thickness of GaN is 1-2 nm; mg doping concentration of 10¹⁷～10¹⁸cm^-3The content y of the Al component is more than or equal to 0.05 and less than or equal to 0.2.

5. The high-brightness LED according to claim 4, wherein the thickness of the high-temperature p-type GaN layer (107) is 100-200 nm, and the Mg doping concentration is 10¹⁷～10¹⁸cm^-3。

6. A high brightness LED according to claim 5, wherein said contact layer (108) is a p-type InGaN contact layer with a thickness of 2-3 nm, Mg doping concentration: 1X 10¹⁸cm^-3～1×10¹⁹cm^-3。

7. The method of manufacturing a high brightness light emitting diode according to claim 6, comprising the steps of:

s1, carrying out surface activation treatment on an AlN/PSS composite substrate (101) in a mixed atmosphere of hydrogen and ammonia at the temperature of 950-1000 ℃;

s2, introducing ammonia gas, and growing a u-shaped GaN merging layer (102) on the AlN/PSS composite substrate (101);

s3, growing an n-type GaN layer (103) on the u-type GaN combined layer (102) in a mixed atmosphere of hydrogen and ammonia, wherein the growth temperature is 1050-1080 ℃, the pressure is 100-150 torr, and the molar ratio of the group V source to the group III source is 1300-1500;

s4, growing a low-temperature GaN V-pits layer (104) on the n-type GaN layer (103) in a nitrogen atmosphere, wherein the growth temperature is 780-860 ℃, the pressure is 300-350torr, and the molar ratio of the group V source to the group III source is 5000-10000;

s5, growing an active region (105) on the low-temperature GaN V-pits layer (104) in a nitrogen atmosphere, wherein the pressure is 300-350torr, and the molar ratio of the group V source to the group III source is 5000-10000;

s6, growing an electron blocking layer (106) on the active region (105) in a nitrogen atmosphere, wherein the pressure is 100-300 torr, and the molar ratio of the group V source to the group III source is 5000-10000;

s7, growing a high-temperature p-type GaN layer (107) on the electron blocking layer (106) in a hydrogen atmosphere, wherein the growth temperature is 950-1050 ℃, the pressure is 100-150 torr, and the molar ratio of the group V source to the group III source is 2000-5000;

s8, growing a contact layer P-InGaN (108) on the high-temperature P-type GaN layer (107) in a hydrogen atmosphere, wherein the growth temperature is 650-750 ℃, the pressure is 300-350torr, and the molar ratio of the group V source to the group III source is 5000-10000; thus obtaining the high-brightness light-emitting diode.

Technical Field

The invention relates to the technical field of light emitting diodes, in particular to a high-brightness light emitting diode based on an AIN/PSS composite substrate and a preparation method thereof.

Background

Existing gallium nitride-based luminescent diodeThe pole conduits are mainly on the polar side:<0001>sapphire and gallium nitride belong to hexagonal crystals, and a GaN thin film is generally grown on heterogeneous sapphire. Due to huge lattice mismatch and thermal mismatch between the two, the Threading Dislocation (TD) density generated in the epitaxial growth process of the GaN thin film is as high as 10⁸～10¹⁰/cm². These TDs are extended approximately vertically by forming a V-shaped defect of 6 sides of {10-11} plane in the shape of an inverted hexagonal pyramid, which is called a V-pit (V-pits).

As a typical characteristic of InGaN/GaN-based LED devices, the role of the V-shaped pit in shielding dislocation and improving the luminous efficiency of the device is widely accepted; with the continuous and deep research, the effect of the V-shaped pits to improve the efficiency of hole injection into the quantum well and improve the uneven distribution of carriers in the well region is gradually known and utilized, so that the photoelectric performance of the InGaN/gan led device is remarkably improved. However, the luminance of the conventional gallium nitride-based light emitting diode is not high enough. Chinese patent application CN101345274A discloses a method for improving the luminous efficiency of GaN-based LEDs using patterned substrates, and the luminance of the GaN-based LEDs made by this method is difficult to meet the current practical needs.

Therefore, development of a light emitting diode with higher luminance is required.

Disclosure of Invention

In order to overcome the defect of insufficient brightness in the prior art, the invention provides the high-brightness light-emitting diode based on the AIN/PSS composite substrate, and the provided light-emitting diode has high light-emitting efficiency and high brightness.

Another object of the present invention is to provide a method for manufacturing the above high-brightness light emitting diode.

In order to solve the technical problems, the invention adopts the technical scheme that:

a high-brightness light-emitting diode based on an AIN/PSS composite substrate comprises an AlN/PSS composite substrate, a u-shaped GaN merging layer, an n-shaped GaN layer, a low-temperature GaN V-pits layer, an active region, an electron blocking layer, a high-temperature p-shaped GaN layer and a contact layer which are sequentially stacked from bottom to top;

the u-shaped GaN merging layer comprises a first u-shaped GaN layer, a second u-shaped GaN layer and a third u-shaped GaN layer which are sequentially stacked from bottom to top; the thickness of the first u-type GaN layer is 0.8-1 mu m, the growth temperature is 1010-1020 ℃, the pressure of a reaction chamber is 200-300 torr, and the molar ratio of the group V source to the group III source is 1000-1200; the thickness of the second u-type GaN layer is 0.8-1 mu m, the growth temperature is 1020-1030 ℃, the pressure of the reaction chamber is 100-150 torr, and the molar ratio of the group V source to the group III source is 1300-1500; the thickness of the third u-type GaN layer is 0.8-1 μm, the growth temperature is 1050-1080 ℃, the pressure of the reaction chamber is 75-100 torr, and the molar ratio of the group V source to the group III source is 1300-1500.

Preferably, the thickness of the n-type GaN layer is 2-3 μm.

Preferably, the low-temperature GaN V-pits layer comprises a first u-GaN layer and an n-GaN layer which are sequentially stacked from bottom to top^--a GaN layer, a second u-GaN layer and n⁺-a GaN layer; wherein the thickness of the first u-GaN layer is 80-90 nm; n is^-The thickness of the GaN layer is 70-80 nm, and the doping concentration of Si is 5 multiplied by 10¹⁷～8×10¹⁷cm^-3(ii) a The thickness of the second u-GaN layer is 80-90 nm; n is⁺The thickness of the GaN layer is 90-100 nm, and the doping concentration of Si is 3 multiplied by 10¹⁸～8×10¹⁸cm^-3。

Preferably, the active region is a triple-gradient InGaN/GaN superlattice structure, and comprises a first gradient, a second gradient and a third gradient which are sequentially stacked from bottom to top; the first gradient is a u-shaped InGaN/GaN superlattice with a period of 10-20 cycles, the thickness of an InGaN well layer with the first gradient is 1-1.5 nm, and the thickness of a GaN barrier layer with the first gradient is 1.5-2 nm; the second gradient is 2-3 periods of n-type InGaN/GaN superlattice, the thickness of the InGaN well layer of the second gradient is 2.5-3 nm, the thickness of the GaN barrier layer of the second gradient is 3-5 nm, and the Si doping concentration is 2 multiplied by 10¹⁸-3×10¹⁸cm^-3(ii) a The third gradient is a 4-6 period u-shaped InGaN/GaN superlattice, the thickness of an InGaN well layer of the third gradient is 2.5-3 nm, and the thickness of a GaN barrier layer of the third gradient is 5-6.5 nm.

Preferably, the electron blocking layer is p-type Al with 5-10 periods_yGa_1-yN/GaN, wherein Al_yGa_1-yN is 1 to2nm, and the thickness of GaN is 1-2 nm; mg doping concentration of 10¹⁷～10¹⁸cm^-3The content y of the Al component is more than or equal to 0.05 and less than or equal to 0.2.

Preferably, the thickness of the high-temperature p-type GaN layer is 100-200 nm, and the Mg doping concentration is 10¹⁷～10¹⁸cm^-3。

Preferably, the contact layer is a p-type InGaN contact layer, the thickness of the contact layer is 2-3 nm, and the Mg doping concentration is 1 x 10¹⁸cm^-3～1×10¹⁹cm^-3。

The invention also provides a preparation method of the high-brightness light-emitting diode, which comprises the following steps:

s1, carrying out surface activation treatment on an AlN/PSS composite substrate (101) in a mixed atmosphere of hydrogen and ammonia at the temperature of 950-1000 ℃;

s2, introducing ammonia gas, and growing a u-shaped GaN merging layer on the AlN/PSS composite substrate (101);

s3, growing an n-type GaN layer on the u-type GaN combined layer in a mixed atmosphere of hydrogen and ammonia, wherein the growth temperature is 1050-1080 ℃, the pressure is 100-150 torr, and the molar ratio of the group V source to the group III source is 1300;

s4, growing a low-temperature GaN V-pits layer on the n-type GaN layer in a nitrogen atmosphere, wherein the growth temperature is 780-860 ℃, the pressure is 300-350torr, and the molar ratio of the group V source to the group III source is 5000-10000;

s5, growing an active region on the low-temperature GaN V-pits layer in a nitrogen atmosphere, wherein the pressure is 300-350torr, and the molar ratio of the group V source to the group III source is 5000-10000;

s6, growing an electron blocking layer on the active region in a nitrogen atmosphere, wherein the pressure is 100-300 torr, and the molar ratio of the group V source to the group III source is 5000-10000;

s7, growing a high-temperature p-type GaN layer on the electron blocking layer in a hydrogen atmosphere, wherein the growth temperature is 950-1050 ℃, the pressure is 100-150 torr, and the molar ratio of the group V source to the group III source is 2000-5000;

s8, growing a contact layer p-InGaN on the high-temperature p-type GaN layer in a hydrogen atmosphere, wherein the growth temperature is 650-750 ℃, the pressure is 300-350torr, and the molar ratio of the group V source to the group III source is 5000-10000; thus obtaining the high-brightness light-emitting diode.

Preferably, steps S1 to S8 are performed in a metal organic compound vapor phase epitaxy reaction chamber.

Preferably, in the step S1, the reaction chamber is processed for 5-10 minutes at a pressure of 100 torr.

Compared with the prior art, the invention has the beneficial effects that:

the invention effectively reduces the dislocation density in the epitaxial material by adopting the AlN/PSS composite substrate, optimally designs the V-pits layer to effectively shield dislocation, designs a novel active region structure on the basis and effectively improves the composite luminous efficiency.

The high-brightness light-emitting diode comprises a u-GaN merging layer with a novel structure, a V-pits layer and an active region, can effectively improve the crystal quality of an epitaxial layer, effectively relieves the stress of the active region, improves the current expansion in the horizontal direction, further realizes the purpose of improving the light-emitting efficiency of the light-emitting diode, and is high in brightness.

Drawings

FIG. 1 is a schematic structural diagram of a high-brightness LED based on AIN/PSS composite substrate according to the present invention.

FIG. 2 is a graph comparing the optical power of the light emitting diodes of examples 1(LED2) to 2(LED3) of the present invention with that of comparative example 1(LED 1).

Detailed Description

The present invention will be further described with reference to the following embodiments.