CN105355735B - A kind of epitaxial growth method of reduction LED contact resistances - Google Patents

Abstract

Disclosure includes growth pInGaN/pGaN superlattice layers after reducing the epitaxial growth method of LED contact resistances, growth doping Mg p-type GaN layer, and growth pInGaN/pGaN superlattice layers are：It is passed through TMGa, H2, Cp₂Mg, TMIn, grow pInGaN/pGaN superlattice layers.PInGaN/pGaN superlattice layers can effectively reduce pGaN epitaxial layers and ITO contact resistance, and can effectively reduce driving voltage；There is hole confinement effect plus pInGaN potential wells, the hole concentration of pInGaN/pGaN superlattice layers can effectively be improved, make pInGaN/pGaN superlattice layers that there is higher hole mobility, the problems such as p layers of resistance and pGaN epitaxial layers and ITO contact resistances are higher, hole concentration is relatively low is effectively solved, is conducive to lifting LED product quality.

Description

A method of epitaxial growth for reducing LED contact resistance

technical field

The present application relates to the technical field of LED epitaxial design application, in particular to an epitaxial growth method for reducing LED contact resistance.

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.

At present, the market is concerned that LEDs are more energy-efficient, have higher brightness and better luminous efficiency, which puts forward higher requirements for LED epitaxial growth; the driving voltage and brightness requirements of high-power devices are the focus of current market demand; LED traditional Among the epitaxial growth methods, the growth of the P layer is the most difficult. The Mg doping efficiency of the P layer and the improvement of the hole concentration are the difficulties and key points. At the same time, the resistance of the P layer and the contact resistance between the P layer and the ITO layer are still high, which affects the performance of the LED. product quality.

Contents of the invention

In view of this, the technical problem to be solved in this application is to provide an epitaxial growth method that reduces the contact resistance of LEDs, effectively solving the problems of p-layer resistance, high contact resistance between pGaN epitaxial layer and ITO, and low hole concentration. , Improve the quality of LED products.

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

An epitaxial growth method for reducing the contact resistance of LEDs, which 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 In _x Ga doped with In _(1-x) N/GaN light-emitting layer, growing a P-type AlGaN layer, growing a P-type GaN layer doped with Mg, cooling down, characterized in that,

After the growth of the Mg-doped P-type GaN layer, the growth of the pInGaN/pGaN superlattice layer is also included, and the growth of the pInGaN/pGaN superlattice layer is:

Keep the reaction chamber pressure at 300mbar-600mbar, temperature at 750°C-850°C, feed 20sccm-40sccm of TMGa, 100L/min-130L/min of H2, 3000sccm-4000sccm of Cp ₂ Mg, 1000sccm-2000sccm of TMIn, and grow pInGaN/ pGaN superlattice layer.

Preferably, wherein the growing undoped Si ₃ N ₄ /GaN superlattice layer is further:

Keep the reaction chamber pressure at 300mbar-600mbar, temperature at 750°C-850°C, feed 20sccm-40sccm of TMGa, 100L/min-130L/min of H2, 3000sccm-4000sccm of Cp ₂ Mg, 1000sccm-2000sccm of TMIn, and grow 1nm- 5nm pInGaN, Mg doping concentration 3E20atoms/cm ³ -4E20atoms/cm ³ , In doping concentration 1E19atoms/cm ³ -5E19atoms/cm ³ ;

Keep the reaction chamber pressure at 300mbar-600mbar, temperature at 750°C-850°C, feed 20sccm-40sccm of TMGa, 100L/min-130L/min of H2, 3000sccm-4000sccm of Cp ₂ Mg, grow 1nm-5nm pGaN, Mg doped Impurity concentration 3E20atoms/cm ³ -4E20atoms/cm ³ ;

Repeat the growth of pInGaN and pGaN, the period is 3-5;

The growth order of pInGaN and pGaN can be replaced.

Preferably, wherein, the processing of the substrate further includes: under the H ₂ atmosphere of 1000°C-1100°C, injecting 100L/min-130L/min of H ₂ , maintaining the pressure of the reaction chamber at 100mbar-300mbar, and processing the sapphire substrate 8min-10min.

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

Cool down to 500°C-600°C, keep the reaction chamber pressure at 300mbar-600mbar, feed in NH3 at a flow rate of 10000sccm-20000sccm, TMGa at 50sccm-100sccm, _H2 at 100L/min-130L/min, and grow on a sapphire substrate to a thickness of The low temperature buffer layer GaN is 20nm-40nm.

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

Preferably, wherein the 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 5E18atoms/cm ³ -1E19atoms/cm ³ ;

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 Si-doped N-type GaN, Si doping concentration 5E17atoms/cm ³ -1E18atoms/cm ³ .

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

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 In _x Ga _(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;

Repeating the growth of In _x Ga _(1-x) N, and then repeating the growth of GaN, alternately growing In _x Ga _(1-x) N/GaN light-emitting layers, and controlling the number of cycles to 7-15.

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

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 -13800sccm Cp ₂ Mg, continuously grow 50nm-100nm P-type AlGaN layer, Al doping concentration 1E20atoms/cm ³ -3E20atoms/cm ³ , Mg doping concentration 1E19atoms/cm ³ -1E20atoms/cm ³ .

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

Keep the reaction chamber pressure at 400mbar-900mbar, temperature at 950°C-1000°C, and flow of NH ₃ at 50000sccm-70000sccm, TMGa at 20sccm-100sccm, _H2 at 100L/min-130sccm, Cp2Mg at _1000sccm -3000sccm , and continuously grow a 50nm-100nm Mg-doped P-type GaN layer with a Mg doping concentration of 1E19atoms/cm ³ -1E20atoms/cm ³ .

Preferably, wherein, the lowering and cooling further includes: lowering the temperature to 650°C-680°C, keeping it warm for 20min-30min, then turning off the heating system and the gas supply system, and cooling with the furnace.

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

In the epitaxial growth method for reducing the LED contact resistance of the present invention, the pInGaN/pGaN superlattice layer is added after growing the Mg-doped P-type GaN layer, and the pInGaN/pGaN superlattice layer can effectively reduce the difference between the pGaN epitaxial layer and ITO. contact resistance, and can effectively reduce the driving voltage; in addition, the pInGaN potential well has a hole confinement effect, which can effectively increase the hole concentration of the pInGaN/pGaN superlattice layer, resulting in a higher pInGaN/pGaN superlattice layer On the one hand, holes can diffuse and conduct, and on the other hand, the pInGaN/pGaN superlattice layer has a low resistance value, so that the driving voltage of the LED device can be reduced, thereby effectively solving the problem of p-layer resistance and pGaN epitaxy. The problem of high contact resistance between layer and ITO, low hole concentration, etc. is beneficial to improve the quality of LED products.

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, 3. undoped GaN, 4. N-type GaN doped with Si, 5. In _x Ga _(1-x) N, 6. GaN, 7. P-type AlGaN, 8, P-type GaN, 9, pInGaN, 10, pGaN.

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 70mbar and 900mbar. The specific growth method is as follows:

An epitaxial growth method for reducing the contact resistance of LEDs, which 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 In _x Ga doped with In _(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.

In the above scheme, the growth of the low-temperature buffer layer GaN further includes: cooling to 500°C-600°C, maintaining the pressure of the reaction chamber at 300mbar-600mbar, feeding NH3 at a flow rate of 10000sccm-20000sccm, TMGa at 50sccm-100sccm, 100L/min-130L/ min of H ₂ , and grow a low-temperature buffer layer GaN with a thickness of 20nm-40nm on a sapphire substrate.

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 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 In _x Ga _(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;

Repeating the growth of In _x Ga _(1-x) N, and then repeating the growth of GaN, alternately growing In _x Ga _(1-x) N/GaN light-emitting layers, and controlling 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. 100sccm-130sccm of TMAl, 1000sccm-1300sccm of Cp ₂ Mg, continuous growth of 50nm-100nm P-type AlGaN layer, Al doping concentration 1E20atoms/cm ³ -3E20atoms/cm ³ , Mg doping concentration 1E19atoms/cm ³ - 1E20 atoms/cm ³ .

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 Cp ₂ Mg, continuous growth of 50nm-100nm Mg-doped P-type GaN layer, Mg doping concentration 1E19atoms/cm ³ -1E20atoms/cm ³ .

After the growth of the Mg-doped P-type GaN layer, the growth of the pInGaN/pGaN superlattice layer is also included, and the growth of the pInGaN/pGaN superlattice layer is:

Keep the reaction chamber pressure at 300mbar-600mbar, temperature at 750°C-850°C, feed 20sccm-40sccm of TMGa, 100L/min-130L/min of H2, 3000sccm-4000sccm of Cp ₂ Mg, 1000sccm-2000sccm of TMIn, and grow pInGaN/ pGaN superlattice layer.

The growing pInGaN/pGaN superlattice layer is further:

Keep the reaction chamber pressure at 300mbar-600mbar, temperature at 750°C-850°C, feed 20sccm-40sccm of TMGa, 100L/min-130L/min of H2, 3000sccm-4000sccm of Cp ₂ Mg, 1000sccm-2000sccm of TMIn, and grow 1nm- 5nm pInGaN, Mg doping concentration 3E20atoms/cm ³ -4E20atoms/cm ³ , In doping concentration 1E19atoms/cm ³ -5E19atoms/cm ³ ;

Keep the reaction chamber pressure at 300mbar-600mbar, temperature at 750°C-850°C, feed 20sccm-40sccm of TMGa, 100L/min-130L/min of H2, 3000sccm-4000sccm of Cp ₂ Mg, grow 1nm-5nm pGaN, Mg doped Impurity concentration 3E20atoms/cm ³ -4E20atoms/cm ³ ;

Repeat the growth of pInGaN and pGaN, the period is 3-5;

The growth order of pInGaN and pGaN can be replaced.

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 epitaxial growth method for reducing the LED contact resistance of the present invention, the pInGaN/pGaN superlattice layer is added after growing the Mg-doped P-type GaN layer, and the pInGaN/pGaN superlattice layer can effectively reduce the difference between the pGaN epitaxial layer and ITO. contact resistance, and can effectively reduce the driving voltage; in addition, the pInGaN potential well has a hole confinement effect, which can effectively increase the hole concentration of the pInGaN/pGaN superlattice layer, resulting in a higher pInGaN/pGaN superlattice layer On the one hand, holes can diffuse and conduct, and on the other hand, the pInGaN/pGaN superlattice layer has a low resistance value, so that the driving voltage of the LED device can be reduced, thereby effectively solving the problem of p-layer resistance and pGaN epitaxy. The problem of high contact resistance between layer and ITO, low hole concentration, etc. is beneficial to improve the quality of LED products.

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 20nm-40nm is grown on it.

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 5E18atoms/cm ³ -1E19atoms/cm ³ (1E19 represents 10 to the 19th power, that is, 10 ¹⁹ , 5E18 represents 5×10 ¹⁸ , and so on in the following representations) .

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 5E17atoms/cm ³ -1E18atoms/cm ³ .

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 In _x Ga _(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 300mbar-400mbar, feed NH ₃ at a flow rate of 50000sccm-70000sccm, TMGa at 20sccm-100sccm, _N2 at 100L/min-130L/min, grow a GaN layer of 8nm-15nm; repeat In _x Ga _(1-x) N The growth of GaN is repeated, and the In _x Ga _(1-x) N/GaN light-emitting layer is alternately grown, and the number of cycles is controlled to be 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 Cp ₂ Mg, continuous growth of 50nm-100nm P-type AlGaN layer, Al doping concentration 1E20atoms/cm ³ -3E20atoms/cm ³ , Mg doping concentration 1E19atoms/cm ³ -1E20atoms/cm ³ .

8. Keep the reaction chamber pressure at 400mbar-900mbar, temperature at 950°C-1000°C, and flow of NH ₃ at 50000sccm-70000sccm, TMGa at 20sccm-100sccm, _H2 at 100sccm-130sccm, and Cp at 1000sccm-3000sccm ₂ Mg, continuously grow 50nm-200nm Mg-doped P-type GaN layer, Mg doping concentration 1E19atoms/cm ³ -1E20atoms/cm ³ .

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.

Sample 1 was prepared according to the traditional LED growth method (comparative example 1 method), and sample 2 was prepared according to the method described in this patent; the difference between sample 1 and sample 2 epitaxial growth method parameters lies in the growth of P-type GaN doped with Mg The growth of pInGaN/pGaN superlattice layer is also included after the layer, and the growth conditions of other epitaxial layers are exactly the same; three pieces of samples 1 and 2 are respectively plated with an ITO layer of about 150nm under the same pre-process conditions, and plated with Cr under the same conditions. The /Pt/Au electrode is about 1500nm, and the protective layer SiO ₂ is about 100nm under the same conditions, and then the sample is ground and cut into 635μm*635μm (25mil*25mil) chip particles under the same conditions, and then sample 1 and sample 2 are in 100 chips are selected at the same position, and packaged into white LEDs under the same packaging process. Then an integrating sphere was used to test the photoelectric performance of samples 1 and 2 under the condition of a driving current of 350mA. Table 1 below is a comparison table of growth parameters of the light-emitting layer, Table 2 is a comparison table of electrical performance parameters of products, and Table 3 is a table of ECV measurement of epitaxial wafers of samples 1 and 2.

Table 1 Comparison of Growth Parameters of Emitting Layer

Table 2 Comparison of electrical parameters of samples 1 and 2

Table 3 ECV measurement of samples 1 and 2 epitaxial wafers

The following conclusions can be drawn from the data in Table 1, Table 2 and Table 3:

Through the growth method provided by this patent, the contact resistance between the epitaxial layer and ITO decreases, the hole concentration of the epitaxial layer pGaN increases, the LED electrical parameter voltage decreases while the brightness increases, and the LED quality is improved. The experimental data proves that the patented solution can improve LED Feasibility of product quality.

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

In the epitaxial growth method for reducing the LED contact resistance of the present invention, the pInGaN/pGaN superlattice layer is added after growing the Mg-doped P-type GaN layer, and the pInGaN/pGaN superlattice layer can effectively reduce the difference between the pGaN epitaxial layer and ITO. contact resistance, and can effectively reduce the driving voltage; in addition, the pInGaN potential well has a hole confinement effect, which can effectively increase the hole concentration of the pInGaN/pGaN superlattice layer, resulting in a higher pInGaN/pGaN superlattice layer On the one hand, holes can diffuse and conduct, and on the other hand, the pInGaN/pGaN superlattice layer has a low resistance value, so that the driving voltage of the LED device can be reduced, thereby effectively solving the problem of p-layer resistance and pGaN epitaxy. The problem of high contact resistance between layer and ITO, low hole concentration, etc. is beneficial to improve the quality of LED products.

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 (9)

1. a kind of epitaxial growth method of reduction LED contact resistances, includes successively：Handle substrate, low temperature growth buffer layer GaN, Grow the GaN layer that undopes, growth doping Si N-type GaN layer, alternating growth doping In In_xGa_(1-x)N/GaN luminescent layers, growth The p-type GaN layer of p-type AlGaN layer, growth doping Mg, cooling down, it is characterised in that

Also include growth p-type InGaN/p type GaN superlattice layers, the growth p-type after the p-type GaN layer of the growth doping Mg InGaN/p type GaN superlattice layers are：

Keep reaction cavity pressure 300mbar-600mbar, 750 DEG C -850 DEG C of temperature, be passed through 20sccm-40sccm TMGa, 100L/min-130L/min H₂, 3000sccm-4000sccm Cp₂Mg, 1000sccm-2000sccm TMIn, growth 1nm-5nm p-type InGaN, Mg doping concentration 3E20atoms/cm³-4E20atoms/cm³, In doping concentrations 1E19atoms/ cm³-5E19atoms/cm³；

Keep reaction cavity pressure 300mbar-600mbar, 750 DEG C -850 DEG C of temperature, be passed through 20sccm-40sccm TMGa, 100L/min-130L/min H₂, 3000sccm-4000sccm Cp₂Mg, grows 1nm-5nm p-type GaN, Mg doping concentration 3E20atoms/cm³-4E20atoms/cm³；

P-type InGaN and p-type GaN growth is repeated, the cycle is 3-5；

P-type InGaN and p-type GaN succession are replaceable.

2. the epitaxial growth method of LED contact resistances is reduced 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. the epitaxial growth method of LED contact resistances is reduced according to claim 1, it is characterised in that

Low temperature growth buffer layer GaN be further：

500 DEG C -600 DEG C are cooled to, reaction cavity pressure 300mbar-600mbar is kept, flow is passed through for 10000sccm- 20000sccm NH₃, 50sccm-100sccm TMGa, 100L/min-130L/min H₂, on a sapphire substrate grow it is thick Spend the low temperature buffer layer GaN for 20nm-40nm.

4. the epitaxial growth method of LED contact resistances is reduced 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.

5. the epitaxial growth method of LED contact resistances is reduced according to claim 4, 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。

6. the epitaxial growth method of LED contact resistances is reduced 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.

7. the epitaxial growth method of LED contact resistances is reduced 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-1300sccm Cp₂Mg, continued propagation 50nm-100nm p-type AlGaN layer, Al doping concentrations 1E20atoms/cm³-3E20atoms/cm³, Mg doping concentrations 1E19atoms/cm³-1E20atoms/cm³。

8. the epitaxial growth method of LED contact resistances is reduced 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-100nm the p-type GaN layer for mixing Mg, Mg doping concentrations 1E19atoms/cm³-1E20atoms/ cm³。

9. according to the epitaxial growth method of any reduction LED contact resistances of claim 1~8, 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.