CN105304773B - A kind of LED outer layer growths method - Google Patents

Abstract

This application discloses a method for growing an epitaxial layer of an LED. The growth of a low-temperature buffer layer GaN is as follows: growing a low-temperature buffer layer GaN-1 on a substrate at a temperature of 500°C-600°C and a pressure of 300mbar-600mbar, and injecting NH ₃ , TMGa, and H ₂ ; Grow buffer layer GaN-2 on GaN-1, temperature is 400°C-480°C, pressure 270mbar-540mbar, feed NH ₃ , TMGa, H ₂ ; grow buffer layer GaN-3 on GaN-2, temperature 320°C -384°C, pressure 243mbar-486mbar, NH ₃ flow rate of 10000sccm-20000sccm, TMGa of 50sccm-100sccm, H ₂ of 100L/min-130L/min. In this way, the dislocation density of the epitaxial layer can be reduced, and the crystal quality of the epitaxial layer can be improved.

Description

A kind of LED epitaxial layer growth method

technical field

The application relates to the technical field of LED epitaxial design and application, in particular, to a method for growing an LED epitaxial layer that can reduce the dislocation density of the epitaxial layer and improve the crystal quality of the epitaxial layer.

Background technique

At present, LED is a kind of solid-state lighting. The advantages of small size, low power consumption, long service life, high brightness, environmental protection, and durability are recognized by consumers. The scale of domestic LED production is also gradually expanding; The demand for growing epitaxial wafers is increasing day by day, and how to grow better epitaxial wafers is getting more and more attention. Because the quality of epitaxial layer crystals improves, the performance of LED devices can be improved, and the luminous efficiency, life, anti-aging ability, antistatic ability, and stability of LEDs will change with With the improvement of the crystal quality of the epitaxial layer, it is improved.

In the existing epitaxial technology, the GaN material is grown on the sapphire Al ₂ O ₃ substrate, because there is about 13% lattice mismatch between the Al ₂ O ₃ material and the GaN material, and the impact is that the dislocation density of the GaN material is as high as 10 ⁹ root/cm ² , the current main method to control the dislocation density is to grow a thin layer of GaN as a buffer layer at low temperature. The existing traditional method of growing GaN buffer layer still has a large dislocation density, which leads to the crystal quality of the grown epitaxial layer not tall.

Contents of the invention

In view of this, the technical problem to be solved in this application is to provide a method for growing an epitaxial layer of an LED, which can reduce the dislocation density of the epitaxial layer, improve the crystal quality of the epitaxial layer, and further enhance the optoelectronic performance of the LED.

In order to solve the above technical problems, the application has the following technical solutions:

A method for growing an LED epitaxial layer, which is characterized in that it sequentially includes: processing a substrate, growing a low-temperature buffer layer GaN, growing an undoped GaN layer, growing an N-type GaN layer doped with Si, and alternately growing _Inx doped with In Ga _(1-x) N/GaN light-emitting layer, growing P-type AlGaN layer, growing Mg-doped P-type GaN layer, cooling down,

The growing low-temperature buffer layer GaN is grown on the substrate in three steps, further comprising:

Grow a low-temperature buffer layer GaN-1 with a thickness of 15nm-30nm on the substrate, the growth temperature is 500°C-600°C, the pressure of the reaction chamber is 300mbar-600mbar, and the flow rate is 10000sccm-20000sccm NH ₃ , 50sccm-100sccm TMGa, 100L/min-130L/min _H2 ;

Grow a buffer layer GaN-2 with a thickness of 10.5nm-21nm on the low-temperature buffer layer GaN-1, the growth temperature is 400°C-480°C, the pressure of the reaction chamber is 270mbar-540mbar, and the flow rate of _NH3 is 10000sccm-20000sccm , TMGa of 50sccm-100sccm, _H2 of 100L/min-130L/min;

Grow a buffer layer GaN-3 with a thickness of 7.35nm-14.7nm on the low-temperature buffer layer GaN-2, the growth temperature is 320°C-384°C, the pressure of the reaction chamber is 243mbar-486mbar, and the flow rate is 10000sccm-20000sccm NH _3. TMGa of 50sccm-100sccm, _H2 of 100L/min-130L/min.

Preferably, wherein said growing the low-temperature buffer layer GaN further includes:

Raise the temperature to 1000°C-1100°C, keep the pressure of the reaction chamber at 300mbar-600mbar, feed in NH ₃ at a flow rate of 30000sccm-40000sccm, and _H2 at 100L/min-130L/min, and keep the temperature stable for 300s-500s , etch the low-temperature buffer layers GaN-1, GaN-2, and GaN-3 into irregular islands.

Preferably, wherein, the processing substrate is: under the H ₂ atmosphere of 1000°C-1100°C, feed 100L/min-130L/min of H ₂ , keep the pressure of the reaction chamber at 100mbar-300mbar, and process the sapphire substrate for 8min -10min.

Preferably, the growth of the undoped GaN layer is as follows: increasing the temperature to 1000°C-1200°C, maintaining the pressure of the reaction chamber at 300mbar-600mbar, feeding NH ₃ at a flow rate of 30000sccm-40000sccm, TMGa at 200sccm-400sccm, 100L/min-130L/min H ₂ , continuously grow 2μm-4μm undoped GaN layer.

Preferably, wherein the growing Si-doped N-type GaN layer is:

Keep the pressure and temperature of the reaction chamber constant, feed in NH ₃ at a flow rate of 30000sccm-60000sccm, TMGa at 200sccm-400sccm, _H2 at 100L/min-130L/min, _SiH4 at 20sccm-50sccm, and continuously grow 3μm-4μm doped Si-doped N-type GaN, Si doping concentration 5E18-1E19;

Keep the pressure and temperature of the reaction chamber constant, feed in NH ₃ at a flow rate of 30000sccm-60000sccm, TMGa at 200sccm-400sccm, _H2 at 100L/min-130L/min, _SiH4 at 2sccm-10sccm, and continuously grow 200nm-400nm doped N-type GaN doped with Si, Si doping concentration 5E17-1E18.

Preferably, wherein, the alternately grown In _x Ga _(1-x) N/GaN light-emitting layer doped with In is:

Keep the pressure of the reaction chamber at 300mbar-400mbar, the temperature at 700°C-750°C, and feed the flow rate of 50000sccm-70000sccm of NH ₃ , 20sccm-40sccm of TMGa, 1500sccm-2000sccm of TMIn, and 100L/min-130L/min of _N2 to grow 2.5nm-3.5nm InxGa(1-x)N layer doped with In, x=0.20-0.25, luminous wavelength 450nm-455nm;

Then raise the temperature to 750°C-850°C, keep the reaction chamber pressure at 300mbar-400mbar, feed NH ₃ at a flow rate of 50000sccm-70000sccm, TMGa at 20sccm-100sccm, and _N2 at 100L/min-130L/min, and grow 8nm- 15nm GaN layer;

Repeat the growth of InxGa(1-x)N, and then repeat the growth of GaN, alternately grow InxGa(1-x)N/GaN light-emitting layers, and control the number of cycles to 7-15.

Preferably, wherein the growing p-type AlGaN layer is:

Keep the pressure of the reaction chamber at 200mbar-400mbar, the temperature at 900°C-950°C, and feed the flow rate of 50000sccm-70000sccm of _NH3 , 30sccm-60sccm of TMGa, 100L/min-130sccm of _H2 , 100sccm-130sccm of TMAl, 1000sccm -1800sccm of Cp2Mg, continuous growth of 50nm-100nm P-type AlGaN layer, Al doping concentration 1E20-3E20, Mg doping concentration 1E19-1E20.

Preferably, wherein the growing Mg-doped P-type GaN layer is:

Keep the pressure of the reaction chamber at 400mbar-900mbar, the temperature at 950°C-1000°C, and the flow rate of 50000sccm-70000sccm of _NH3 , 20sccm-100sccm of TMGa, 100L/min-130L/min of _H2 , 1000sccm-3000sccm of Cp2Mg, continuous A Mg-doped P-type GaN layer of 50nm-200nm is grown, and the Mg doping concentration is 1E19-1E20.

Preferably, wherein, the cooling is as follows: lower the temperature to 650°C-680°C, keep warm for 20min-30min, then turn off the heating system, turn off the gas supply system, and cool down with the furnace.

Compared with the prior art, the method described in this application has achieved the following effects:

First, GaN materials are grown on sapphire Al ₂ O ₃ substrates in the existing epitaxial technology, because Al ₂ O ₃ materials and GaN materials have a lattice mismatch of about 13%, which affects the dislocation density of GaN materials As high as 10 ⁹ /cm ² , in the LED epitaxial layer growth method of the present invention, by regularly changing the growth conditions, the buffer layer GaN is grown in three steps, which can reduce the dislocation density of the LED epitaxial layer to a greater extent compared with the traditional method , improve the crystal quality of the epitaxial layer, and then help to improve the photoelectric performance of the LED.

Second, the crystal quality of the epitaxial layer produced by the method for growing the LED epitaxial layer of the present invention is better, and the produced LED device has high brightness, low voltage and small electric leakage.

Description of drawings

The drawings described here are used to provide a further understanding of the application and constitute a part of the application. The schematic embodiments and descriptions of the application are used to explain the application and do not constitute an improper limitation to the application. In the attached picture:

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

Fig. 2 is the structural representation of LED epitaxial layer in comparative example 1;

Among them, 1. substrate, 2. buffer layer GaN-1, 3, buffer layer GaN-2, 4, buffer layer GaN-3, 5, undoped GaN, 6, n-type GaN doped with Si, 7, In _x Ga _(1-x) N, 8, GaN, 9, P-type AlGaN, 10, P-type GaN, 11, buffer layer GaN.

detailed description

Certain terms are used, for example, in the description and claims to refer to particular components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not use the difference in name as a way to distinguish components, but use the difference in function of components as a criterion for distinguishing. As mentioned throughout the specification and claims, "comprising" is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. In addition, the term "coupled" herein includes any direct and indirect electrical coupling means. Therefore, if it is described that a first device is coupled to a second device, it means that the first device may be directly electrically coupled to the second device, or indirectly electrically coupled through other devices or coupling means. connected to the second device. The subsequent description of the specification is a preferred implementation mode for implementing the application, but the description is for the purpose of illustrating the general principle of the application, and is not intended to limit the scope of the application. The scope of protection of the present application should be defined by the appended claims.

Example 1

Referring to Fig. 1, the present invention uses MOCVD to grow high-brightness GaN-based LED epitaxial wafers. Use high-purity _H2 or high-purity _N2 or a mixed gas of high-purity _H2 and high-purity _N2 as the carrier gas, high-purity _NH3 as the N source, metal-organic source trimethylgallium (TMGa) as the gallium source, three Methyl indium (TMIn) is used as indium source, N-type dopant is silane (SiH ₄ ), trimethylaluminum (TMAl) is used as aluminum source, P-type dopant is dichloromagnesium (CP ₂ Mg), substrate For (0001) sapphire, the reaction pressure is between 100mbar and 800mbar. The specific growth method is as follows:

A method for growing an LED epitaxial layer, comprising: processing a substrate, growing a low-temperature buffer layer GaN, growing an undoped GaN layer, growing an N-type GaN layer doped with Si, and alternately growing In _x Ga _{(1- x)} N/GaN light-emitting layer, growing a P-type AlGaN layer, growing a Mg-doped P-type GaN layer, and cooling down, wherein,

The above step of processing the substrate is as follows: under the H ₂ atmosphere at 1000°C-1100°C, feed 100L/min-130L/min H ₂ , keep the reaction chamber pressure at 100mbar-300mbar, and process the sapphire substrate for 8min-10min.

The above-mentioned growth of the low-temperature buffer layer GaN can be divided into three steps to grow the buffer layer on the sapphire substrate, specifically:

Grow a low-temperature buffer layer GaN-1 with a thickness H1 of 15nm-30nm on the substrate, the growth temperature T1 is 500°C-600°C, the pressure P1 of the reaction chamber is 300mbar-600mbar, and the flow rate is 10000sccm-20000sccm (sccm is the standard Milliliters per minute) of NH ₃ , 50sccm-100sccm of TMGa, 100L/min-130L/min of H ₂ ;

Grow a buffer layer GaN-2 with a thickness H2 of 10.5nm-21nm on the low-temperature buffer layer GaN-1, where H2=0.7H1; growth temperature T2 is 400°C-480°C, where T2=0.8T1; The pressure P2 is 270mbar-540mbar, wherein, P2=0.9P1; the flow rate is 10000sccm-20000sccm of _NH3 , 50sccm-100sccm of TMGa, 100L/min-130L/min of _H2 ;

Grow a buffer layer GaN-3 with a thickness H3 of 7.35nm-14.7nm on the low-temperature buffer layer GaN-2, where H3=0.7H2; growth temperature T3 is 320°C-384°C, where T3=0.8T2; reaction chamber The pressure P3 is 243mbar-486mbar, wherein, P3=0.9P2; the flow rate of NH ₃ is 10000sccm-20000sccm, TMGa is 50sccm-100sccm, and _H2 is 100L/min-130L/min.

In the above solution, growing the low-temperature buffer layer GaN may further include: raising the temperature to 1000°C-1100°C, maintaining the pressure of the reaction chamber at 300mbar-600mbar, feeding NH ₃ at a flow rate of 30000sccm-40000sccm, 100L/min-130L/ Min H ₂ , keep the temperature stable, last for 300s-500s, etch the low-temperature buffer layers GaN-1, GaN-2, GaN-3 into irregular small islands.

The above-mentioned growth of the undoped GaN layer further includes: increasing the temperature to 1000°C-1200°C, maintaining the pressure of the reaction chamber at 300mbar-600mbar, feeding NH ₃ at a flow rate of 30000sccm-40000sccm, TMGa at 200sccm-400sccm, and 100L/min-130L /min H ₂ , continuously grow 2μm-4μm undoped GaN layer.

The above-mentioned growing Si-doped N-type GaN layer is further:

Keep the pressure and temperature of the reaction chamber constant, feed in NH ₃ at a flow rate of 30000sccm-60000sccm, TMGa at 200sccm-400sccm, _H2 at 100L/min-130L/min, _SiH4 at 20sccm-50sccm, and continuously grow 3μm-4μm doped N-type GaN doped with Si, Si doping concentration 5E18-1E19 (1E19 represents 10 to the 19th power, that is, 10 ¹⁹ , 5E18 represents 5×10 ¹⁸ , and so on in the following representation);

Keep the pressure and temperature of the reaction chamber constant, feed in NH ₃ at a flow rate of 30000sccm-60000sccm, TMGa at 200sccm-400sccm, _H2 at 100L/min-130L/min, _SiH4 at 2sccm-10sccm, and continuously grow 200nm-400nm doped N-type GaN doped with Si, Si doping concentration 5E17-1E18.

The above-mentioned In _x Ga _(1-x) N/GaN light-emitting layer doped with In alternately grown as follows:

Keep the pressure of the reaction chamber at 300mbar-400mbar, the temperature at 700°C-750°C, and feed the flow rate of 50000sccm-70000sccm of NH ₃ , 20sccm-40sccm of TMGa, 1500sccm-2000sccm of TMIn, and 100L/min-130L/min of _N2 to grow 2.5nm-3.5nm InxGa(1-x)N layer doped with In, x=0.20-0.25, luminous wavelength 450nm-455nm;

Then raise the temperature to 750°C-850°C, keep the reaction chamber pressure at 300mbar-400mbar, feed NH ₃ at a flow rate of 50000sccm-70000sccm, TMGa at 20sccm-100sccm, and _N2 at 100L/min-130L/min, and grow 8nm- 15nm GaN layer;

Repeat the growth of InxGa(1-x)N, and then repeat the growth of GaN, alternately grow InxGa(1-x)N/GaN light-emitting layers, and control the number of cycles to 7-15.

The above growth of the P-type AlGaN layer further includes: maintaining the pressure of the reaction chamber at 200mbar-400mbar, the temperature at 900°C-950°C, and feeding NH ₃ at a flow rate of 50000sccm-70000sccm, TMGa at 30sccm-60sccm, and H at 100L/min-130L/min. _2. TMAl of 100sccm-130sccm, Cp2Mg of 1000sccm-1800sccm, continuously grow P-type AlGaN layer of 50nm-100nm, Al doping concentration 1E20-3E20, Mg doping concentration 1E19-1E20.

The above-mentioned growth of the Mg-doped P-type GaN layer further includes: maintaining the pressure of the reaction chamber at 400mbar-900mbar, the temperature at 950°C-1000°C, and feeding NH ₃ at a flow rate of 50000sccm-70000sccm, TMGa at 20sccm-100sccm, 100L/min-130L/ Min of H ₂ , 1000sccm-3000sccm of Cp2Mg, continuous growth of 50nm-200nm Mg-doped P-type GaN layer, Mg doping concentration 1E19-1E20.

The above-mentioned cooling is further carried out as follows: lower the temperature to 650°C-680°C, keep warm for 20min-30min, then turn off the heating system, turn off the gas supply system, and cool with the furnace.

In the LED epitaxial layer growth method of the present invention, by regularly changing the growth conditions, the buffer layer GaN is grown in three steps. Compared with the traditional method, the dislocation density of the LED epitaxial layer can be reduced to a greater extent, and the crystal quality of the epitaxial layer can be improved. It is beneficial to improve the photoelectric performance of LED.

Comparative Example 1

The growth method of the traditional LED epitaxial layer is (refer to Figure 2 for the epitaxial layer structure):

1. Under the H ₂ atmosphere at 1000°C-1100°C, feed H ₂ at 100L/min-130L/min, keep the reaction chamber pressure at 100mbar-300mbar, and process the sapphire substrate for 8min-10min.

2. Lower the temperature to 500-600°C, keep the pressure of the reaction chamber at 300mbar-600mbar, and feed in NH ₃ at a flow rate of 10000sccm-20000sccm, TMGa at 50sccm-100sccm, and _H2 at 100L/min-130L/min on the sapphire substrate A low-temperature buffer layer GaN with a thickness of 30nm-50nm is grown on top; at an elevated temperature of 1000-1100°C, the pressure of the reaction chamber is maintained at 300mbar-600mbar, and the flow rate of 30000sccm-40000sccm of NH ₃ and 100L/min-130L/min of H _2. Keep the temperature stable for 300s-500s, etch the low-temperature buffer layer GaN into irregular islands.

3. High temperature up to 1000°C-1200°C, keep the pressure of the reaction chamber at 300mbar-600mbar, feed the flow rate of 30000sccm-40000sccm of NH ₃ , 200sccm-400sccm of TMGa, 100L/min-130L/min of H ₂ , and continue to grow 2μm -4 μm undoped GaN layer.

4. Keep the pressure and temperature of the reaction chamber constant, feed in NH ₃ at a flow rate of 30000sccm-60000sccm, TMGa at 200sccm-400sccm, _H2 at 100L/min-130L/min, and _SiH4 at 20sccm-50sccm, and continue to grow 3μm- 4μm Si-doped N-type GaN, Si doping concentration 5E18-1E19 (1E19 represents 10 to the 19th power, that is, 10 ¹⁹ , 5E18 represents 5×10 ¹⁸ , and so on).

5. Keep the pressure and temperature of the reaction chamber constant, feed in NH ₃ at a flow rate of 30000sccm-60000sccm, TMGa at 200sccm-400sccm, _H2 at 100L/min-130L/min, _SiH4 at 2sccm-10sccm, and grow continuously at 200nm- 400nm N-type GaN doped with Si, Si doping concentration 5E17-1E18.

6. Keep the pressure of the reaction chamber at 300mbar-400mbar, the temperature at 700°C-750°C, and the flow rate of 50000sccm-70000sccm of NH ₃ , 20sccm-40sccm of TMGa, 1500sccm-2000sccm of TMIn, and 100L/min-130L/min of _N2 , grow an InxGa(1-x)N layer of 2.5nm-3.5nm doped with In, x=0.20-0.25, and the emission wavelength is 450nm-455nm; then raise the temperature to 750°C-850°C, and keep the reaction chamber pressure at 300mbar- 400mbar, feed NH ₃ at a flow rate of 50000sccm-70000sccm, TMGa at 20sccm-100sccm, and _N2 at 100L/min-130L/min, grow a GaN layer of 8nm-15nm; repeat the growth of InxGa(1-x)N, and then The growth of GaN is repeated, the InxGa(1-x)N/GaN light-emitting layer is alternately grown, and the number of control cycles is 7-15.

7. Keep the pressure of the reaction chamber at 200mbar-400mbar, the temperature at 900°C-950°C, and the flow rate of NH ₃ at 50000sccm-70000sccm, TMGa at 30sccm-60sccm, _H2 at 100sccm-130sccm, and TMAl at 100sccm-130sccm , 1000sccm-1800sccm Cp2Mg, continuous growth of 50nm-100nm P-type AlGaN layer, Al doping concentration 1E20-3E20, Mg doping concentration 1E19-1E20.

8. Keep the pressure of the reaction chamber at 400mbar-900mbar, the temperature at 950°C-1000°C, and the flow rate of 50000sccm-70000sccm of _NH3 , 20sccm-100sccm of TMGa, 100L/min-130L/min of _H2 , and 1000sccm-3000sccm of Cp2Mg , and continuously grow a 50nm-200nm Mg-doped P-type GaN layer with a Mg doping concentration of 1E19-1E20.

9. Finally, cool down to 650°C-680°C, keep warm for 20min-30min, then turn off the heating system and gas supply system, and cool down with the furnace.

Next, according to the traditional LED epitaxial layer growth method, ie, the method of Comparative Example 1, 4 samples 1 were prepared, and 4 samples 2 were prepared according to the method described in this patent. The only difference between the growth methods of sample 1 and sample 2 is the method of growing buffer layer GaN, and the other growth steps are exactly the same. After the growth, take out the XRD102 surface of the epitaxial wafer and test it under the same conditions, please refer to Table 1. Sample 1 and sample 2 were plated with an ITO layer of about 1500 angstroms under the same pre-process conditions, plated a Cr/Pt/Au electrode with about 2500 angstroms under the same conditions, and plated a protective layer of SiO ₂ with about 500 angstroms under the same conditions. The samples were ground and cut into 762μm*762μm (30mi*30mil) chip particles under certain conditions, and then sample 1 and sample 2 each selected 100 chips at the same position, and packaged them into white LEDs under the same packaging process. The following tests were carried out (1) photoelectric performance test: the photoelectric performance of sample 1 and sample 2 was tested on the same LED point measuring machine under the condition of driving current 350mA, see Table 2.

Table 1 Epitaxial XRD test data of sample 1 and sample 2

Table 2 Photoelectric test data of LED testing machine for sample 1 and sample 2

The following conclusions can be drawn from the data in Table 1 and Table 2:

(1) Table 1 shows that the XRD102 surface value of the sample produced by the patented technology becomes smaller, indicating that the crystal quality of the epitaxial layer of the sample produced by the patented technology is relatively good, and it is obviously better.

(2) Table 2 shows that the sample LED device produced by this patented technology has high brightness, low voltage, and small leakage. This is due to the fact that the buffer layer GaN grown by this patented technology reduces the dislocation of the epitaxial layer and improves the crystal quality of the epitaxial layer. Improve the photoelectric performance of LED.

Can know by above each embodiment, the beneficial effect that the present application exists is:

First, GaN materials are grown on sapphire Al ₂ O ₃ substrates in the existing epitaxial technology, because Al ₂ O ₃ materials and GaN materials have a lattice mismatch of about 13%, which affects the dislocation density of GaN materials As high as 10 ⁹ /cm ² , in the LED epitaxial layer growth method of the present invention, by regularly changing the growth conditions, the buffer layer GaN is grown in three steps, which can reduce the dislocation density of the LED epitaxial layer to a greater extent compared with the traditional method , improve the crystal quality of the epitaxial layer, and then help to improve the photoelectric performance of the LED.

Second, the crystal quality of the epitaxial layer produced by the method for growing the LED epitaxial layer of the present invention is better, and the produced LED device has high brightness, low voltage and small electric leakage.

Those skilled in the art should understand that the embodiments of the present application may be provided as methods, apparatuses, or computer program products. 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, etc.) having computer-usable program code embodied therein.

The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various Various other combinations, modifications, and environments can be made within the scope of the inventive concept described herein, by the above teachings or by skill or knowledge in the relevant field. However, modifications and changes made by those skilled in the art do not depart from the spirit and scope of the present application, and should all be within the protection scope of the appended claims of the present application.

Claims (8)

1. a kind of LED outer layer growths method, includes successively：Handle substrate, low temperature growth buffer layer GaN, grow the GaN that undopes Layer, growth doping Si N-type GaN layer, alternating growth doping In In_xGa_(1-x)N/GaN luminescent layers, growing P-type AlGaN layer, life Long doping Mg p-type GaN layer, cooling down, it is characterised in that

Low temperature growth buffer layer GaN is point three steps in Grown, further for：

In the low temperature buffer layer GaN-1 that Grown thickness is 15nm-30nm, growth temperature is 500 DEG C -600 DEG C, reaction chamber Pressure be 300mbar-600mbar, be passed through flow be 10000sccm-20000sccm NH₃, 50sccm-100sccm TMGa, 100L/min-130L/min H₂；

Growth thickness is 10.5nm-21nm cushion GaN-2 on low temperature buffer layer GaN-1, and growth temperature is 400 DEG C -480 DEG C, the pressure of reaction chamber is 270mbar-540mbar, is passed through the NH that flow is 10000sccm-20000sccm₃、50sccm- 100sccm TMGa, 100L/min-130L/min H₂；

On low temperature buffer layer GaN-2 growth thickness be 7.35nm-14.7nm cushion GaN-3, growth temperature be 320 DEG C- 384 DEG C, the pressure of reaction chamber is 243mbar-486mbar, is passed through the NH that flow is 10000sccm-20000sccm₃、 50sccm-100sccm TMGa, 100L/min-130L/min H₂；

The low temperature growth buffer layer GaN further comprises：

It is 300mbar-600mbar that temperature, which is raised, to reaction cavity pressure at 1000 DEG C -1100 DEG C, is kept, and being passed through flow is 30000sccm-40000sccm NH₃, 100L/min-130L/min H₂, keeping temperature stabilization, lasting 300s-500s will be low Warm cushion GaN-1, GaN-2, GaN-3 corrode into irregular island.

2. LED outer layer growths method according to claim 1, it is characterised in that

It is described processing substrate be further：In 1000 DEG C -1100 DEG C of H₂Under atmosphere, 100L/min-130L/min H is passed through₂, Keep reaction cavity pressure 100mbar-300mbar, processing Sapphire Substrate 8min-10min.

3. LED outer layer growths method according to claim 1, it is characterised in that

The growth GaN layer that undopes is further：1000 DEG C -1200 DEG C are increased the temperature to, reaction cavity pressure is kept 300mbar-600mbar, is passed through the NH that flow is 30000sccm-40000sccm₃, 200sccm-400sccm TMGa, 100L/min-130L/min H₂, 2 μm -4 μm of continued propagation the GaN layer that undopes.

4. LED outer layer growths method according to claim 3, it is characterised in that

It is described growth doping Si N-type GaN layer be further：

Reaction cavity pressure, temperature-resistant is kept, the NH that flow is 30000sccm-60000sccm is passed through₃、200sccm-400sccm TMGa, 100L/min-130L/min H₂, 20sccm-50sccm SiH₄, 3 μm of -4 μm of doping Si of continued propagation N-type GaN, Si doping concentration 5E18atoms/cm³-1E19atoms/cm³；

Reaction cavity pressure, temperature-resistant is kept, the NH that flow is 30000sccm-60000sccm is passed through₃、200sccm-400sccm TMGa, 100L/min-130L/min H₂, 2sccm-10sccm SiH₄, continued propagation 200nm-400nm doping Si N-type GaN, Si doping concentration 5E17atoms/cm³-1E18atoms/cm³。

5. LED outer layer growths method according to claim 1, it is characterised in that

The In of the alternating growth doping In_xGa_(1-x)N/GaN luminescent layers are further：

Reaction cavity pressure 300mbar-400mbar, 700 DEG C -750 DEG C of temperature are kept, flow is passed through for 50000sccm- 70000sccm NH₃, 20sccm-40sccm TMGa, 1500sccm-2000sccm TMIn, 100L/min-130L/min N₂, growth doping In 2.5nm-3.5nm In_xGa_(1-x)N layers, x=0.20-0.25, emission wavelength 450nm-455nm；

Then rise temperature keeps reaction cavity pressure 300mbar-400mbar, being passed through flow is to 750 DEG C -850 DEG C 50000sccm-70000sccm NH₃, 20sccm-100sccm TMGa, 100L/min-130L/min N₂, grow 8nm- 15nm GaN layer；

Repeat In_xGa_(1-x)N growth, then repeatedly GaN growth, alternating growth In_xGa_(1-x)N/GaN luminescent layers, control week Issue is 7-15.

6. LED outer layer growths method according to claim 1, it is characterised in that

The growing P-type AlGaN layer is further：

Reaction cavity pressure 200mbar-400mbar, 900 DEG C -950 DEG C of temperature are kept, flow is passed through for 50000sccm- 70000sccm NH₃, 30sccm-60sccm TMGa, 100L/min-130L/min H₂, 100sccm-130sccm TMAl, 1000sccm-1800sccm Cp2Mg, continued propagation 50nm-100nm p-type AlGaN layer, Al doping concentrations 1E20atoms/cm³-3E20atoms/cm³, Mg doping concentrations 1E19atoms/cm³-1E20atoms/cm³。

7. LED outer layer growths method according to claim 1, it is characterised in that

Described grow mixes Mg p-type GaN layer and is further：

Reaction cavity pressure 400mbar-900mbar, 950 DEG C -1000 DEG C of temperature are kept, flow is passed through for 50000sccm- 70000sccm NH₃, 20sccm-100sccm TMGa, 100L/min-130L/min H₂, 1000sccm-3000sccm Cp2Mg, continued propagation 50nm-200nm the p-type GaN layer for mixing Mg, Mg doping concentrations 1E19atoms/cm³-1E20atoms/ cm³。

8. according to any LED outer layer growths method of claim 1~7, it is characterised in that

The cooling down is further：Be cooled to 650 DEG C -680 DEG C, be incubated 20min-30min, be then switched off heating system, Close and give gas system, furnace cooling.