CN109950369B

CN109950369B - LED epitaxial P layer growth method

Info

Publication number: CN109950369B
Application number: CN201910222332.7A
Authority: CN
Inventors: 徐平; 冯磊; 王杰
Original assignee: Xiangneng Hualei Optoelectrical Co Ltd
Current assignee: Xiangneng Hualei Optoelectrical Co Ltd
Priority date: 2019-03-22
Filing date: 2019-03-22
Publication date: 2021-06-25
Anticipated expiration: 2039-03-22
Also published as: CN109950369A

Abstract

The application discloses a growth method of an LED epitaxial P layer, which sequentially comprises the following steps: processing substrate, growing low-temperature buffer layer GaN, growing undoped GaN layerGrowing an N-type GaN layer doped with Si, and alternately growing In doped with In_ZGa_(1‑Z)The method comprises the following steps of N/GaN light emitting layer growing a P-type AlGaN layer, growing a P layer doped with Mg, and cooling. The epitaxial P layer growth method of the invention utilizes In_xMg_(1‑x)N/In_yMg_(1‑y)The N layer can greatly reduce the warping of the epitaxial wafer, improve the product percent of pass and improve the luminous efficiency.

Description

LED epitaxial P layer growth method

Technical Field

The application relates to the technical field of LED epitaxial design application, in particular to a method for growing an LED epitaxial P layer.

Background

An LED (Light Emitting Diode) is a solid lighting, and is approved by consumers due to its advantages of small size, low power consumption, long service life, high brightness, environmental protection, firmness and durability, etc., the scale of domestic production of LEDs is gradually expanding, and the size of LEDs produced by most manufacturers is upgraded to 4 inches from 2 inches. After the size of the LED is upgraded to 4 inches, the LED generally has the technical problems of large warpage of the epitaxial wafer, low light emitting efficiency, low product yield and the like, so how to reduce the warpage of the epitaxial wafer and improve the product yield is a technical problem which needs to be solved urgently in the field.

Disclosure of Invention

In view of the above, the present application provides a method for growing an epitaxial P layer of an LED by using In_xMg_(1-x)N/In_yMg_(1-y)The N layer can greatly reduce the warping of the epitaxial wafer, improve the product percent of pass and improve the luminous efficiency.

In order to solve the technical problem, the following technical scheme is adopted:

a growth method of an epitaxial P layer of an LED sequentially comprises the following steps: processing a substrate, growing a GaN low-temperature buffer layer, growing an undoped GaN layer, growing an N-type GaN layer doped with Si, and alternately growing In doped with In_ZGa_(1-Z)An N/GaN luminous layer, a P-type AlGaN layer, a P layer doped with Mg, and cooling,

the growing Mg-doped P layer is further as follows:

keeping the pressure of the reaction cavity at 400mbar-900mbar and the temperature at 950-1000 ℃, and introducing NH with the flow rate of 50000sccm-70000sccm₃TMIn of 500sccm-1000sccm, H of 100L/min-130L/min₂Cp of 100sccm to 300sccm₂In with Mg grown to a thickness of D1_xMg_(1-x)N layer, D1 is more than or equal to 500nm and less than or equal to 600nm, the value range of x is 0.1-0.3, the growth time is 500s, and the Mg doping concentration is increased by 4E +16atoms/cm per second³From 4E +19atoms/cm³A linear ramp increase of 6E +19atoms/cm³；

Maintaining the growth temperature, the growth pressure, NH₃、H₂TMIn flow constant, Cp₂The flow rate of the introduced Mg is controlled to be 200sccm-400sccm, and the In is_xMg_(1-x)In with the thickness of D2 is grown on the N layer_yMg_(1-y)N layer, D2 is more than or equal to 200nm and less than or equal to 240nm, the value range of y is 0.15-0.45, the growth time is 250s, and the Mg doping concentration is increased by 8E +15atoms/cm per second³From 2E +18atoms/cm³A linear ramp increase of 4E +18atoms/cm³；

Wherein, D1 is 2.5D2, and y is 1.5 x;

repeating the periodic growth of In_xMg_(1-x)N/In_yMg_(1-y)N layers, and the cycle number is 5-9.

Preferably, wherein the processing substrate is further: h at 1000-1100 deg.C₂Introducing H of 100L/min-130L/min under the atmosphere₂And keeping the pressure of the reaction cavity at 100mbar-300mbar, and processing the sapphire substrate for 8min-10 min.

Preferably, wherein the grown GaN low-temperature buffer layer is further: cooling to 500-600 deg.C, maintaining the pressure in the reaction chamber at 300-600 mbar, and introducing NH with a flow rate of 10000-20000 sccm₃TMGa of 50sccm-100sccm and H of 100L/min-130L/min₂Growing a GaN low-temperature buffer layer with the thickness of 20nm-40nm on the sapphire substrate; raising the temperature to 1000-1100 ℃, keeping the pressure of the reaction cavity at 300mbar-600mbar, and introducing NH with the flow rate of 30000sccm-40000sccm₃、100L/min-130L/miH of n₂And keeping the temperature stable for 300-500 s, and corroding the GaN low-temperature buffer layer into irregular islands.

Preferably, wherein the growing undoped GaN layer is further: raising the temperature to 1000-1200 ℃, keeping the pressure of the reaction cavity at 300mbar-600mbar, and introducing NH with the flow rate of 30000sccm-40000sccm₃TMGa of 200sccm-400sccm, H of 100L/min-130L/min₂And continuously growing the undoped GaN layer of 2-4 mu m.

Preferably, wherein the growing of the N-type GaN layer doped with Si is further: keeping the pressure and the temperature of the reaction cavity unchanged, and introducing NH with the flow rate of 30000sccm-60000sccm₃TMGa of 200sccm-400sccm, H of 100L/min-130L/min₂20sccm to 50sccm SiH₄Continuously growing N-type GaN doped with Si of 3 μm-4 μm with a Si doping concentration of 5E18atoms/cm³-1E19atoms/cm³(ii) a Keeping the pressure and the temperature of the reaction cavity unchanged, and introducing NH with the flow rate of 30000sccm-60000sccm₃TMGa of 200sccm-400sccm, H of 100L/min-130L/min₂2sccm-10sccm SiH₄Continuously growing N-type GaN doped with Si of 200 μm-400 μm with a Si doping concentration of 5E17atoms/cm³-1E18atoms/cm³。

Preferably, wherein the alternately growing In doped with In_ZGa_(1-Z)The N/GaN light-emitting layer further comprises: keeping the pressure of the reaction cavity at 300mbar-400mbar and the temperature at 700-750 ℃, and introducing NH with the flow rate of 50000sccm-70000sccm₃20sccm to 40sccm of TMGa, 1500sccm to 2000sccm of TMIn, 100L/min to 130L/min of N₂Growing In doped with In at 2.5nm to 3.5nm_ZGa_(1-Z)An N layer, wherein Z is 0.20-0.25, and the light-emitting wavelength is 450nm-455 nm; then raising the temperature to 750-850 ℃, keeping the pressure of the reaction cavity at 300mbar-400mbar, and introducing NH with the flow rate of 50000sccm-70000sccm₃20sccm-100sccm of TMGa and 100L/min-130L/min of N₂Growing a GaN layer with the thickness of 8nm-15 nm; repeating In_ZGa_(1-Z)Growth of N, and then repeating growth of GaN to alternately grow In_ZGa_(1-Z)The N/GaN luminescent layer has a control cycle number of 7-15.

Preferably, wherein said growth is P-typeThe AlGaN layer is further: keeping the pressure of the reaction cavity between 200mbar and 400mbar and the temperature between 900 ℃ and 950 ℃, and introducing NH with the flow rate between 50000sccm and 70000sccm₃TMGa of 30sccm-60sccm and H of 100L/min-130L/min₂TMAl of 100sccm-130sccm, Cp of 1000sccm-1300sccm₂Mg, continuously growing a P-type AlGaN layer with the thickness of 50nm to 100nm and the Al doping concentration of 1E20atoms/cm³-3E20atoms/cm³Mg doping concentration of 1E19atoms/cm³-1E20atoms/cm³。

Preferably, wherein the cooling step further comprises: cooling to 650-680 ℃, preserving heat for 20-30 min, then closing the heating system and the gas supply system, and cooling along with the furnace.

Compared with the prior art, the method has the following effects:

(1) in the method for growing the epitaxial P layer of the LED, In is introduced_xMg_(1-x)N/In_yMg_(1-y)The N layer controls the regular gradual change of Mg doping concentration in the growth process, the Mg doping efficiency can be improved, the crystallization quality of the layer can be improved, the stress accumulation effect of the sapphire substrate on the GaN film can be eliminated, the stress control window of the epitaxial film material can be obviously increased, the warping of the epitaxial wafer can be reduced, the qualified rate of the GaN epitaxial wafer can be improved, and the LED luminous efficiency and the antistatic capacity can be improved.

(2) First growing In with high Mg doping concentration_xMg_(1-x)The N layer can prevent defects generated by lattice mismatch in the early stage from extending upwards, so that the dislocation density is reduced, the crystal quality is improved, and the performances of LED brightness, electric leakage, static resistance and the like are improved. Regrown of In with lower Mg doping concentration_yMg_(1-y)The N layer can enable the epitaxial atoms to be uniformly filled upwards, can improve the growth uniformity of materials in the wafer, reduces a polarization field generated in the epitaxial growth process, promotes the epitaxial layer atoms to release the wafer internal stress, and accordingly reduces warping.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 is a schematic structural diagram of an LED epitaxial layer in embodiment 1 of the present invention;

FIG. 2 is a schematic view showing the structure of an epitaxial layer of an LED in comparative example 1;

wherein, 1, a substrate, 2, a GaN low-temperature buffer layer, 3, an undoped GaN layer, 4, an N-type GaN layer, 5 and In_ZGa_(1-Z)N layer, 6 GaN layer, 7P type AlGaN layer, 8 In_xMg_(1-x)N layer, 9, In_yMg_(1-y)N layer, 56, In_ZGa_(1-Z)N/GaN luminescent layer, 89, P layer.

Detailed Description

As used in the specification and in the claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The protection scope of the present application shall be subject to the definitions of the appended claims.

Example 1

Referring to fig. 1, the present invention uses MOCVD to grow a high brightness GaN-based LED epitaxial wafer, referring to fig. 1. By using high-purity H₂Or high purity N₂Or high purity H₂And high purity N₂The mixed gas of (2) is used as a carrier gas, high-purity NH₃As the N source, a metal organic source, trimethyl gallium (TMGa) as the gallium source, trimethyl indium (TMIn) as the indium source, and an N-type dopant, Silane (SiH)₄) Trimethylaluminum (TMAl) as the aluminum source and a P-type dopant of bisCyclopentadienyl magnesium (CP)₂Mg), the substrate 1 is (0001) plane sapphire, and the reaction pressure is between 70mbar and 900 mbar. The specific growth mode is as follows:

a growth method of an LED epitaxial P layer 89 sequentially comprises the following steps: processing a substrate 1, growing a GaN low-temperature buffer layer 2, growing an undoped GaN layer 3, growing an N-type GaN layer 4 doped with Si, and alternately growing In doped with In_ZGa_(1-Z)N/GaN luminescent layer 56, growth P type AlGaN layer 7, growth Mg-doped P layer 89, cooling, specifically:

processing the substrate 1, further: h at 1000-1100 deg.C₂Introducing H of 100L/min-130L/min under the atmosphere₂The pressure of the reaction cavity is kept between 100mbar and 300mbar, and the thickness of the sapphire substrate 1 is processed for 8min to 10 min.

Growing a GaN low-temperature buffer layer 2, further: cooling to 500-600 deg.C, maintaining the pressure in the reaction chamber at 300-600 mbar, introducing NH3 with flow rate of 10000-20000 sccm, TMGa with flow rate of 50-100 sccm, and H with flow rate of 100-130L/min₂Growing a GaN low-temperature buffer layer 2 with the thickness of 20nm-40nm on the sapphire substrate 1; raising the temperature to 1000-1100 ℃, keeping the pressure of the reaction cavity at 300mbar-600mbar, and introducing NH with the flow rate of 30000sccm-40000sccm₃H of 100L/min-130L/min₂Keeping the temperature stable for 300-500 s, and corroding the GaN low-temperature buffer layer 2 into irregular islands.

Growing an undoped GaN layer 3, further: raising the temperature to 1000-1200 ℃, keeping the pressure of the reaction cavity at 300mbar-600mbar, and introducing NH with the flow rate of 30000sccm-40000sccm₃TMGa of 200sccm-400sccm, H of 100L/min-130L/min₂And continuously growing the undoped GaN layer 3 with the thickness of 2-4 mu m.

Growing an N-type GaN layer 4 doped with Si, further: keeping the pressure and the temperature of the reaction cavity unchanged, and introducing NH with the flow rate of 30000sccm-60000sccm₃TMGa of 200sccm-400sccm, H of 100L/min-130L/min₂20sccm to 50sccm SiH₄Continuously growing N-type GaN doped with Si of 3 μm-4 μm with a Si doping concentration of 5E18atoms/cm³-1E19 atoms/cm³(ii) a Keeping the pressure and the temperature of the reaction cavity unchanged, and introducing NH with the flow rate of 30000sccm-60000sccm₃、200TMGa of sccm-400sccm, H of 100L/min-130L/min₂2sccm-10sccm SiH₄Continuously growing a Si-doped N-type GaN layer 4 of 200 μm-400 μm with a Si doping concentration of 5E17atoms/cm³-1E18atoms/cm³。

Alternatively growing In doped with In_ZGa_(1-Z)The N/GaN light emitting layer 56, further: keeping the pressure of the reaction cavity at 300mbar-400mbar and the temperature at 700-750 ℃, and introducing NH with the flow rate of 50000sccm-70000sccm₃20sccm to 40sccm of TMGa, 1500sccm to 2000sccm of TMIn, 100L/min to 130L/min of N₂Growing In doped with In at 2.5nm to 3.5nm_ZGa_(1-Z)An N layer 5, wherein Z is 0.20-0.25, and the light-emitting wavelength is 450nm-455 nm; then raising the temperature to 750-850 ℃, keeping the pressure of the reaction cavity at 300mbar-400mbar, and introducing NH with the flow rate of 50000sccm-70000sccm₃20sccm-100sccm of TMGa and 100L/min-130L/min of N₂Growing a GaN layer 6 with the thickness of 8nm-15 nm; repeating In_ZGa_(1-Z)Growth of N, and then repeating growth of GaN to alternately grow In_ZGa_(1-Z)The number of control cycles of the N/GaN light emitting layer 56 is 7-15.

Growing a P-type AlGaN layer 7, further comprising: keeping the pressure of the reaction cavity between 200mbar and 400mbar and the temperature between 900 ℃ and 950 ℃, and introducing NH with the flow rate between 50000sccm and 70000sccm₃TMGa of 30sccm-60sccm and H of 100L/min-130L/min₂TMAl of 100sccm-130sccm, Cp of 1000sccm-1300sccm₂Mg, continuously growing a P-type AlGaN layer 7 with the thickness of 50nm to 100nm, and the Al doping concentration of 1E20atoms/cm³-3E20 atoms/cm³Mg doping concentration of 1E19atoms/cm³-1E20 atoms/cm³。

Growing a Mg-doped P layer 89, further:

keeping the pressure of the reaction cavity at 400mbar-900mbar and the temperature at 950-1000 ℃, and introducing NH with the flow rate of 50000sccm-70000sccm₃TMIn of 500sccm-1000sccm, H of 100L/min-130L/min₂Cp of 100sccm to 300sccm₂In with Mg grown to a thickness of D1_xMg_(1-x)N layer 8, D1 is more than or equal to 500nm and less than or equal to 600nm, x is in the range of 0.1-0.3, the growth time is 500s, and the Mg doping concentration is increased by 4E +16atoms/cm per second³From 4E +19atoms/cm³A linear ramp increase of 6E +19atoms/cm³；

Maintaining the growth temperature, the growth pressure, NH₃、H₂TMIn flow constant, Cp₂The flow rate of the introduced Mg is controlled to be 200sccm-400sccm, and the In is_xMg_(1-x)In with a thickness of D2 was grown on the N layer 8_yMg_(1-y)D2 is more than or equal to 200nm and less than or equal to 240nm of the N layer 9, the value range of y is 0.15-0.45, the growth time is 250s, and the Mg doping concentration is increased by 8E +15atoms/cm per second³From 2E +18atoms/cm³A linear ramp increase of 4E +18atoms/cm³；

Wherein, D1 is 2.5D2, and y is 1.5 x;

Cooling, further: cooling to 650-680 ℃, preserving heat for 20-30 min, then closing the heating system and the gas supply system, and cooling along with the furnace.

Comparative example 1

Comparative example 1 provides a conventional LED epitaxial layer growth method (see fig. 2 for an epitaxial layer structure):

1. h at 1000-1100 deg.C₂Introducing H of 100L/min-130L/min under the atmosphere₂And keeping the pressure of the reaction cavity at 100mbar-300mbar, and processing the thickness of the sapphire substrate 1 for 8min-10 min.

2. Cooling to 500-600 ℃, keeping the pressure of the reaction chamber at 300mbar-600mbar, and introducing NH with the flow rate of 10000sccm-20000sccm₃TMGa of 50sccm-100sccm and H of 100L/min-130L/min₂And growing a GaN low-temperature buffer layer 2 with the thickness of 20nm-40nm on the sapphire substrate 1. Raising the temperature to 1000-1100 ℃, keeping the pressure of the reaction cavity at 300mbar-600mbar, and introducing NH with the flow rate of 30000sccm-40000sccm₃H of 100L/min-130L/min₂Keeping the temperature stable for 300-500 s, and corroding the GaN low-temperature buffer layer 2 into irregular islands.

3. Raising the temperature to 1000-1200 ℃, keeping the pressure of the reaction cavity at 300mbar-600mbar, and introducing NH with the flow rate of 30000sccm-40000sccm₃TMGa of 200sccm-400sccm, H of 100L/min-130L/min₂And continuously growing the undoped GaN layer 3 with the thickness of 2-4 μm.

4. Keeping the pressure and the temperature of the reaction cavity unchanged, and introducing NH with the flow rate of 30000sccm-60000sccm₃TMGa of 200sccm-400sccm, H of 100L/min-130L/min₂20sccm to 50sccm SiH₄Continuously growing N-type GaN doped with Si of 3 μm-4 μm with a Si doping concentration of 5E18atoms/cm³-1E19 atoms/cm³(1E19 represents the power of 19 of 10, i.e. 10¹⁹And 5E18 represents 5X 10¹⁸The following notation is analogized).

5. Keeping the pressure and the temperature of the reaction cavity unchanged, and introducing NH with the flow rate of 30000sccm-60000sccm₃TMGa of 200sccm-400sccm, H of 100L/min-130L/min₂2sccm-10sccm SiH₄Continuously growing N-type GaN doped with Si of 200nm-400nm with the Si doping concentration of 5E17atoms/cm³-1E18 atoms/cm³。

6. Keeping the pressure of the reaction cavity at 300mbar-400mbar and the temperature at 700-750 ℃, and introducing NH with the flow rate of 50000sccm-70000sccm₃20sccm to 40sccm of TMGa, 1500sccm to 2000sccm of TMIn, 100L/min to 130L/min of N₂Growing In doped with In at 2.5nm to 3.5nm_ZGa_(1-Z) An N layer 5, wherein Z is 0.20-0.25, and the light-emitting wavelength is 450nm-455 nm; then raising the temperature to 750-850 ℃, keeping the pressure of the reaction cavity at 300mbar-400mbar, and introducing NH with the flow rate of 50000sccm-70000sccm₃20sccm-100sccm of TMGa and 100L/min-130L/min of N₂Growing a GaN layer 6 with the thickness of 8nm-15 nm; repeating In_ZGa_(1-Z)Growth of N, and then repeating growth of GaN to alternately grow In_ZGa_(1-Z)The number of control cycles of the N/GaN light emitting layer 56 is 7-15.

7. Keeping the pressure of the reaction cavity between 200mbar and 400mbar and the temperature between 900 ℃ and 950 ℃, and introducing NH with the flow rate between 50000sccm and 70000sccm₃TMGa of 30sccm-60sccm and H of 100L/min-130L/min₂TMAl of 100sccm-130sccm, Cp of 1000sccm-1800sccm₂Mg, continuously growing a P-type AlGaN layer 7 with the thickness of 50nm to 100nm, and the Al doping concentration of 1E20atoms/cm³-3E20atoms/cm³Doping with MgConcentration 1E19atoms/cm³-1E20 atoms/cm³。

8. Keeping the pressure of the reaction cavity at 400mbar-900mbar and the temperature at 950-1000 ℃, and introducing NH with the flow rate of 50000sccm-70000sccm₃20sccm-100sccm of TMGa and 100L/min-130L/min of H₂Cp of 1000sccm-3000sccm₂Mg, continuously growing a P-type GaN layer doped with Mg with the concentration of 1E19atoms/cm and the thickness of 50nm-200nm³-1E20 atoms/cm³。

9. And finally, cooling to 650-680 ℃, preserving the temperature for 20-30 min, then closing the heating system, closing the gas supply system, and cooling along with the furnace.

1000 samples 1 were prepared according to the prior art LED epitaxial growth method and 1000 samples 2 were prepared according to the method described in this patent. The warpage BOW values of the epitaxial wafers were measured under the same conditions by randomly selecting 8 wafers of each of the

samples

1 and 2, and please refer to table 1, wherein table 1 shows the warpage test data of the epitaxial wafers of the

samples

1 and 2. Sample 1 and sample 2 were plated with an ITO layer at about 1500 angstroms under the same pre-process conditions, a Cr/Pt/Au electrode at about 2500 angstroms under the same conditions, and a protective SiO2 layer at about 500 angstroms under the same conditions, and then the samples were ground and cut into 762 μm (30 mil) chip particles under the same conditions, and then 100 dies were picked from each of sample 1 and sample 2 at the same locations and packaged into white LEDs under the same packaging process. And (3) carrying out photoelectric performance test: the same LED spot-measuring machine tests the photoelectric properties of sample 1 and sample 2 under the condition of driving current 350mA, please refer to table 2, and table 2 shows the photoelectric property test data of sample 1 and sample 2.

Table 1 warpage data for epitaxial wafers of sample 1 and sample 2

Table 2 photoelectric test data of sample 1 and sample 2LED tester

As can be seen from table 1, the warpage of the epitaxial wafer prepared by the LED epitaxial growth method provided by the present invention is significantly reduced. In addition, statistics on grinding and fragment conditions of 1000 samples 1 and 1000 samples 2 shows that 36 samples 1 and 19 samples 2 are fragmented, namely the fragment rate of the sample 1 is 3.6% and the fragment rate of the sample 2 is 1.9%.

As can be seen from table 2, the sample 2 prepared by the LED epitaxial growth method provided by the present invention has high brightness, low voltage, and good antistatic capability, and the full width at half maximum of the sample 2 is smaller than the full width at half maximum of the sample 1, which indicates that the LED prepared by the LED epitaxial growth method provided by the present invention has better wavelength uniformity, more concentrated wavelength, and better photoelectric properties.

Compared with the prior art, the method has the following effects:

(1) in the method for growing the LED epitaxial P layer 89, InxMg is introduced_(1-x)N/InyMg_(1-y)The N layer controls the regular gradual change of Mg doping concentration in the growth process, the Mg doping efficiency can be improved, the crystallization quality of the layer can be improved, the stress accumulation effect of the sapphire substrate 1 on the GaN film can be eliminated, the stress control window of the epitaxial film material can be obviously increased, the warping of the epitaxial wafer can be reduced, the qualified rate of the GaN epitaxial wafer can be improved, and the LED luminous efficiency and the antistatic capacity can be improved.

(2) First growing In with high Mg doping concentration_xMg_(1-x)The N layer 8 can prevent defects generated by lattice mismatch in the early stage from extending upwards, so that the dislocation density is reduced, the crystal quality is improved, and the performances of LED brightness, electric leakage, static resistance and the like are improved. Regrown of In with lower Mg doping concentration_yMg_(1-y) The N layer 9 can enable the epitaxial atoms to be uniformly filled upwards, can improve the growth uniformity of materials in the wafer, reduces a polarization field generated in the epitaxial growth process, promotes the epitaxial layer atoms to release the wafer internal stress, and accordingly reduces warping.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, apparatus, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.

Claims

1. A growth method of an epitaxial P layer of an LED sequentially comprises the following steps: processing a substrate, growing a GaN low-temperature buffer layer, growing an undoped GaN layer, growing an N-type GaN layer doped with Si, and alternately growing In doped with In_ZGa_(1-Z)An N/GaN luminous layer, a P-type AlGaN layer, a P layer doped with Mg, and cooling,

the growing Mg-doped P layer is further as follows:

Maintaining growth temperature, growth pressure, NH₃、H₂TMIn flowConstant amount, Cp₂The flow rate of the introduced Mg is controlled to be 200sccm-400sccm, and the In is_xMg_(1-x)In with the thickness of D2 is grown on the N layer_yMg_(1-y)N layer, D2 is more than or equal to 200nm and less than or equal to 240nm, y is in the range of 0.15-0.45, the growth time is 250s, and the Mg doping concentration is increased by 8E +15atoms/cm per second³From 2E +18atoms/cm³A linear ramp increase of 4E +18atoms/cm³；

Wherein, D1 is 2.5D2, and y is 1.5 x;

2. The LED epitaxial P layer growth method according to claim 1,

the processing substrate is further: h at 1000-1100 deg.C₂Introducing H of 100L/min-130L/min under the atmosphere₂And keeping the pressure of the reaction cavity at 100mbar-300mbar, and processing the sapphire substrate for 8min-10 min.

3. The LED epitaxial P layer growth method according to claim 1,

the GaN low-temperature buffer layer further comprises:

cooling to 500-600 deg.C, maintaining the pressure in the reaction chamber at 300-600 mbar, and introducing NH with a flow rate of 10000-20000 sccm₃TMGa of 50sccm-100sccm and H of 100L/min-130L/min₂Growing a GaN low-temperature buffer layer with the thickness of 20nm-40nm on the sapphire substrate;

raising the temperature to 1000-1100 ℃, keeping the pressure of the reaction cavity at 300mbar-600mbar, and introducing NH with the flow rate of 30000sccm-40000sccm₃H of 100L/min-130L/min₂And keeping the temperature stable for 300-500 s, and corroding the GaN low-temperature buffer layer into irregular islands.

4. The LED epitaxial P layer growth method according to claim 1,

the growing undoped GaN layer further comprises: the temperature is raised to 1000-1200 ℃,keeping the pressure of the reaction cavity at 300mbar-600mbar, and introducing NH with the flow rate of 30000sccm-40000sccm₃TMGa of 200sccm-400sccm, H of 100L/min-130L/min₂And continuously growing the undoped GaN layer of 2-4 mu m.

5. The LED epitaxial P layer growth method according to claim 4,

the growing of the Si-doped N-type GaN layer further comprises the following steps:

keeping the pressure and the temperature of the reaction cavity unchanged, and introducing NH with the flow rate of 30000sccm-60000sccm₃TMGa of 200sccm-400sccm, H of 100L/min-130L/min₂20sccm to 50sccm SiH₄Continuously growing N-type GaN doped with Si of 3 μm-4 μm with a Si doping concentration of 5E18atoms/cm³-1E19atoms/cm³；

Keeping the pressure and the temperature of the reaction cavity unchanged, and introducing NH with the flow rate of 30000sccm-60000sccm₃TMGa of 200sccm-400sccm, H of 100L/min-130L/min₂2sccm-10sccm SiH₄Continuously growing N-type GaN doped with Si of 200 μm-400 μm with a Si doping concentration of 5E17atoms/cm³-1E18atoms/cm³。

6. The LED epitaxial P layer growth method according to claim 1,

the alternately grown In doped with In_ZGa_(1-Z)The N/GaN light-emitting layer further comprises:

keeping the pressure of the reaction cavity at 300mbar-400mbar and the temperature at 700-750 ℃, and introducing NH with the flow rate of 50000sccm-70000sccm₃20sccm to 40sccm of TMGa, 1500sccm to 2000sccm of TMIn, 100L/min to 130L/min of N₂Growing In doped with In at 2.5nm to 3.5nm_ZGa_(1-Z)An N layer, wherein Z is 0.20-0.25, and the light-emitting wavelength is 450nm-455 nm;

then raising the temperature to 750-850 ℃, keeping the pressure of the reaction cavity at 300mbar-400mbar, and introducing NH with the flow rate of 50000sccm-70000sccm₃20sccm-100sccm of TMGa and 100L/min-130L/min of N₂Growing a GaN layer with the thickness of 8nm-15 nm;

repeating In_ZGa_(1-Z)Growth of N, and then repeating growth of GaN to alternately grow In_ZGa_(1-Z)The N/GaN luminescent layer has a control cycle number of 7-15.

7. The LED epitaxial P layer growth method according to claim 1,

the growing P-type AlGaN layer further comprises:

keeping the pressure of the reaction cavity between 200mbar and 400mbar and the temperature between 900 ℃ and 950 ℃, and introducing NH with the flow rate between 50000sccm and 70000sccm₃TMGa of 30sccm-60sccm and H of 100L/min-130L/min₂TMAl of 100sccm-130sccm, Cp of 1000sccm-1300sccm₂Mg, continuously growing a P-type AlGaN layer with the thickness of 50nm to 100nm and the Al doping concentration of 1E20atoms/cm³-3E20atoms/cm³Mg doping concentration of 1E19atoms/cm³-1E20atoms/cm³。

8. The LED epitaxial P layer growth method according to claim 1,

the cooling is further as follows: cooling to 650-680 ℃, preserving heat for 20-30 min, then closing the heating system and the gas supply system, and cooling along with the furnace.