CN107785465A - A kind of LED epitaxial buffer layers growing method - Google Patents

Abstract

This application provides a kind of LED epitaxial buffer layers growing method, including：Prepare MgZnO high-purity ceramic targets；Sapphire Substrate is put into magnetron sputtering reaction chamber, grows MgZnO film on a sapphire substrate；The Sapphire Substrate taking-up for having MgZnO film will be grown, place into MOCVD reaction chambers, successively growth doping Si N-type GaN layer, active layer MQW, p-type AlGaN layer and p-type GaN layer；Annealing.The present invention grows MgZnO film by using magnetically controlled sputter method as cushion on a sapphire substrate, reduces LED epitaxial growth defects, improves electronics and the combined efficiency in hole, lifts LED luminous efficiency.

Description

A kind of LED epitaxial buffer layer growth method

technical field

The invention belongs to the technical field of LEDs, and in particular relates to a method for growing an epitaxial buffer layer of an LED.

Background technique

LED (Light Emitting Diode, Light Emitting Diode) is a kind of solid-state lighting. Due to the advantages of LED, such as small size, low power consumption, long service life, high brightness, environmental protection, and durability, it is recognized by consumers, and the scale of domestic LED production is also increasing. Gradually expand.

Sapphire is the most common substrate material for industrial growth of GaN-based LEDs at this stage. Due to the lattice mismatch between the sapphire substrate and GaN, it is necessary to reduce the lattice defect density in GaN-based LED devices by growing various buffer layers.

The growth methods of the traditional LED epitaxial layer are: processing the substrate, growing a low-temperature buffer layer GaN, growing a 3D GaN layer, growing a 2D GaN layer, growing an N-type GaN layer doped with Si, periodically growing an active layer MQW, and growing a P-type AlGaN layer. layer, growing a Mg-doped P-type GaN layer, and cooling down.

In the above-mentioned traditional epitaxial technology, GaN materials are grown on sapphire (Al ₂ O ₃ ) substrates, because there is a large lattice mismatch between Al ₂ O ₃ materials and GaN materials, and the impact is that the dislocation density of GaN materials is as high as 109/cm ² , which affects the improvement of the luminous efficiency of the GaN LED chip; and there are disadvantages such as poor thermal conductivity of the substrate, serious light absorption, and difficulty in peeling off. At present, the main method to control the dislocation density is to grow a thin layer of GaN as a buffer layer at low temperature, and then perform 3D growth and 2D growth of GaN on this basis, and finally form a relatively flat GaN layer.

The following provides a traditional LED epitaxial growth method:

1. Treat the sapphire substrate for 5min-10min at a temperature of 900°C-1100°C, a reaction chamber pressure of 100-200mbar, and 50-100L/min of H ₂ ;

2. Growth of low temperature buffer GaN layer;

3. A 3D GaN layer of 2 μm-3 μm is grown.

4. A 2D GaN layer of 2 μm-3 μm is grown.

5. Growth of N-type GaN layer doped with Si;

6. Periodically grow the active layer MQW;

7. Growth of 50nm-100nm P-type AlGaN layer;

8. Growing a Mg-doped P-type GaN layer of 100nm-300nm;

9. At a temperature of 700°C-800°C, feed 100L/min-150L/min of _N2 , keep warm for 20min-30min, and cool with the furnace.

Although the traditional buffer layer technology has been able to reduce the lattice mismatch between Al ₂ O ₃ materials and GaN materials to a certain extent, and improve the luminous efficiency of GaN-based LED light-emitting devices to a certain extent, the use of traditional buffer layer , Whether it is between the buffer layer and the sapphire substrate or between the buffer layer and the N-type GaN layer, there are still a large number of defects.

Therefore, it is a technical problem to be solved urgently in this technical field to provide a method for growing an LED epitaxial buffer layer to further reduce material defects and improve the luminous efficiency of LEDs.

Contents of the invention

In order to solve the problem that there are still a large number of defects between the buffer layer and the sapphire substrate and between the buffer layer and the N-type GaN layer after the traditional buffer layer is adopted in the background technology, the present invention discloses a LED epitaxial buffer layer growth method, which can Further reduce the epitaxial growth defects of LED, increase the recombination efficiency of electrons and holes, and improve the luminous efficiency of LED.

In order to solve the problems in the above-mentioned background technology, the present invention provides a method for growing an LED epitaxial buffer layer, including:

Select high-purity (99.999%) ZnO and MgO powders, mix ZnO and MgO powders in a ratio of 1:1-1:1.2, compact them in the mold of a 130-150MPa hydraulic press, and then burn them in the air for 8-10 hours , to obtain MgZnO high-purity alloy ceramic target;

Put the sapphire substrate into the magnetron sputtering reaction chamber, use the above-mentioned MgZnO high-purity alloy ceramic target as the target material, the distance between the target material and the sapphire substrate is 7-10cm, and the temperature in the chamber is 150-250°C. The cavity pressure is 1-1.5Pa, the radio frequency power is 100-140W, 10-40sccm oxygen and 70-280sccm argon are introduced, and the flow rate ratio of oxygen and argon is controlled to be 1:7. Grow a 150-200nm thick MgZnO film on the bottom, and the growth time is 15-20min;

Put the sapphire substrate on which the MgZnO film is grown into an MOCVD reaction chamber, and sequentially grow a Si-doped N-type GaN layer, an active layer MQW, a P-type AlGaN layer, and a P-type GaN layer;

At a temperature of 700°C-800°C, under the condition of feeding 100L/min-150L/min of N ₂ , keep it warm for 20-30min, and cool with the furnace.

Further, at a temperature of 1000°C-1100°C and a reaction chamber pressure of 150-300mbar, 50-90L/min of H ₂ , 40-60L/min of NH ₃ , 200-300sccm of TMGa, 20-50sccm of Under the condition of SiH ₄ , a 2 μm-4 μm thick Si-doped N-type GaN layer is grown, and the Si doping concentration is 5×10 ¹⁸ atoms/cm ³ -1×10 ¹⁹ atoms/cm ³ .

Further, the sapphire substrate is processed for 5 minutes to 10 minutes at a temperature of 900° C. to 1100° C., a reaction chamber pressure of 100 to 200 mbar, and 50 to 100 L/min of H ₂ flowing in.

Further, the active layer MQW includes: alternately grown In _x Ga _(1-x) N well layers and GaN barrier layers, and the alternating period is controlled at 10-15.

Further, at a temperature of 700°C-750°C and a reaction chamber pressure of 300mbar-400mbar, 50-90L/min of _N2 , 40-60L/min of _NH3 , 10-50sccm of TMGa, 1000-2000sccm of Under the condition of TMIn, the In _x Ga _(1-x) N well layer with a thickness of 3nm-4nm is grown, wherein,

x=0.15-0.25,

In doping concentration is 1×10 ²⁰ atoms/cm ³ -3×10 ²⁰ atoms/cm ³ .

Further, under the condition that the temperature is 800°C-850°C, 50-90 L/min of N ₂ , 40-60 L/min of NH ₃ , and 10-50 sccm of TMGa are fed, the said GaN barrier layer.

Further, under the conditions of temperature 850-950°C, reaction chamber pressure 200r-400mbar, 50-90L/min _N2 , 40-60L/min _NH3 , 50-100sccm TMGa, grow Mg The P-type AlGaN layer is doped.

Further, the thickness of the P-type AlGaN layer doped with Mg is 50nm-100nm; wherein,

Al doping concentration is 1×10 ²⁰ atoms/cm ³ -3×10 ²⁰ atoms/cm ³ ;

The Mg doping concentration is 5×10 ¹⁸ atoms/cm ³ -1×10 ¹⁹ atoms/cm ³ .

Further, under the conditions of high temperature of 950°C-1000°C, reaction chamber pressure of 200-600mbar, 50-90L/min of _N2 , 40-60L/min of _NH3 , and 50-100sccm of TMGa, The P-type GaN layer doped with Mg is grown.

Further, the thickness of the P-type GaN layer doped with Mg is 100nm-300nm, wherein,

The Mg doping concentration is 1×10 ¹⁹ atoms/cm ³ -1×10 ²⁰ atoms/cm ³ .

Compared with the prior art, the LED epitaxial buffer layer growth method described in this application achieves the following effects:

The LED epitaxial buffer layer growth method provided by the present invention, by utilizing the magnetron sputtering method to grow high-quality MgZnO thin film on the sapphire substrate as buffer layer, utilizes MgZnO material Zn ²⁺ (0.060nm) and Mg ²⁺ (0.057nm ) ionic radius is close, Zn ²⁺ (0.060nm) and Mg ²⁺ replace each other in the oxide lattice to form MgZnO, the lattice distortion caused by this substitutional mixed crystal is small, between MgZnO and GaN and MgZnO The state of complete relaxation between the sapphire substrate and the sapphire substrate is achieved, the stress caused by lattice mismatch is basically eliminated, the defects such as dislocations generated during material growth are greatly reduced, the wave function overlap of electrons and holes increases, and the electrons and holes The recombination efficiency of holes increases, and the number of photons generated by recombination per unit time increases, thereby improving the luminous efficiency of the LED.

In addition, the MgZnO material has a wider adjustable bandgap range (3.3-7.8ev), which increases the effective barrier height of the quantum barrier, effectively confines and blocks electrons from overflowing from the quantum well, and suppresses the generation of electron leakage current. , thereby improving the injection efficiency of electrons and holes in the quantum well, and improving the luminous efficiency of the LED.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute improper limitations to the present invention. In the attached picture:

FIG. 1 is a schematic structural view of LED epitaxy prepared by the method for growing an LED epitaxial buffer layer in Example 1;

Fig. 2 is the schematic structural diagram of LED epitaxy prepared by LED epitaxial buffer layer growth method in embodiment 2;

FIG. 3 is a schematic diagram of an LED epitaxial structure prepared by a traditional LED epitaxial growth method in the prior art.

Detailed ways

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. 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.

In addition, this specification does not limit the components and method steps disclosed in the claims to the components and method steps of the embodiments. In particular, the dimensions, materials, shapes, structural order, adjacent order, and manufacturing method of the components described in the embodiments are merely illustrative examples and do not limit the scope of the present invention thereto unless otherwise specified. . The size and positional relationship of structural components shown in the drawings are shown enlarged for clarity of explanation.

The present application will be described in further detail below in conjunction with the accompanying drawings, but it is not intended to limit the present application.

Example 1

FIG. 1 is a schematic structural diagram of LED epitaxy prepared by using the LED epitaxy buffer layer growth method provided in this embodiment. Please refer to FIG. 1, the LED epitaxy includes: a MgZnO thin film 102, an N-type GaN layer 103, an active layer MQW104, a P-type AlGaN layer 105, and a P-type GaN layer 106 grown sequentially on a sapphire substrate 101; The source layer MQW104 includes alternately grown In _x Ga _(1-x) N well layers 1041 and GaN barrier layers 1042 , and the alternating period is controlled at 10-15.

The LED epitaxial buffer layer growth method described in this embodiment includes:

Step 11: growing a MgZnO thin film on a sapphire substrate.

Specifically, high-purity (99.999%) ZnO and MgO powders are selected, and ZnO and MgO powders are mixed in a ratio of 1:1-1:1.2, compacted in a mold of a 130-150MPa hydraulic press, and then burned in air 8-10h, get MgZnO high-purity alloy ceramic target;

Put the sapphire substrate into the magnetron sputtering reaction chamber, use the above-mentioned MgZnO high-purity alloy ceramic target as the target material, the distance between the target material and the sapphire substrate is 7-10cm, and the temperature in the chamber is 150-250°C. The cavity pressure is 1-1.5Pa, the radio frequency power is 100-140W, 10-40sccm oxygen and 70-280sccm argon are introduced, and the flow rate ratio of oxygen and argon is controlled to be 1:7. A 150-200nm thick MgZnO film is grown on the bottom, and the growth time is 15-20min.

Step 12: Take out the sapphire substrate on which the MgZnO film is grown from the magnetron sputtering reaction chamber, put it into the MOCVD reaction chamber by metal-organic chemical vapor deposition, and grow doped Si on the sapphire with the MgZnO film grown on it N-type GaN layer.

Step 13: Periodically grow the MQW active layer.

Step 14: growing a P-type AlGaN layer.

Step 15: growing a Mg-doped P-type GaN layer.

Step 16: Under the condition that the temperature is 700°C-800°C and 100L/min-150L/min of N ₂ is fed, keep it warm for 20-30min, and cool with the furnace.

The present invention grows a high-quality MgZnO thin film on a sapphire substrate as a buffer layer by utilizing the magnetron sputtering method, utilizes the MgZnO material Zn ²⁺ (0.060nm) and Mg ²⁺ (0.057nm) with close ion radii, Zn ²⁺ ( 0.060nm) and Mg ²⁺ replace each other in their respective oxide lattices to form MgZnO. The lattice distortion caused by this substitutional mixed crystal is small, and complete relaxation is achieved between MgZnO and GaN and between MgZnO and sapphire substrate. The stress caused by lattice mismatch is basically eliminated, the defects such as dislocations generated during material growth are greatly reduced, the wave function overlap degree of electrons and holes increases, and the recombination efficiency of electrons and holes increases. The number of photons generated by internal recombination increases, thereby improving the luminous efficiency of the LED.

In addition, the MgZnO material has a wider adjustable bandgap range (3.3-7.8ev), which increases the effective barrier height of the quantum barrier, effectively confines and blocks electrons from overflowing from the quantum well, and suppresses the generation of electron leakage current. , thereby improving the injection efficiency of electrons and holes in the quantum well, and improving the luminous efficiency of the LED.

Example 2

Fig. 2 is a schematic structural diagram of LED epitaxy prepared by using the LED epitaxy buffer layer growth method provided in this embodiment. Please refer to FIG. 2, the LED epitaxy includes: a MgZnO thin film 202, an N-type GaN layer 203, an active layer MQW204, a P-type AlGaN layer 205, and a P-type GaN layer 206 grown on a sapphire substrate 201 in sequence; The source layer MQW204 includes alternately grown In _x Ga _(1-x) N well layers 2041 and GaN barrier layers 2042 , and the alternating period is controlled at 10-15.

The ZnO-based GaN-based LED epitaxial growth method described in this embodiment specifically includes:

Step 21: growing a MgZnO thin film on a sapphire substrate.

Specifically, high-purity (99.999%) ZnO and MgO powders are selected, and ZnO and MgO powders are mixed in a ratio of 1:1-1:1.2, compacted in a mold of a 130-150MPa hydraulic press, and then burned in air 8-10h, get MgZnO high-purity alloy ceramic target;

Put the sapphire substrate into the magnetron sputtering reaction chamber, use the above-mentioned MgZnO high-purity alloy ceramic target as the target material, the distance between the target material and the sapphire substrate is 7-10cm, and the temperature in the chamber is 150-250°C. The cavity pressure is 1-1.5Pa, the radio frequency power is 100-140W, 10-40sccm oxygen and 70-280sccm argon are introduced, and the flow rate ratio of oxygen and argon is controlled to be 1:7. A 150-200nm thick MgZnO film is grown on the bottom, and the growth time is 15-20min.

Step 22: In the MOCVD reaction chamber, an N-type GaN layer doped with Si is grown.

Specifically, the sapphire substrate on which the MgZnO thin film is deposited is put into an MOCVD reaction chamber, and at a temperature of 1000°C-1100°C and a pressure of 150-300mbar in the reaction chamber, 50-90L/min of H ₂ , 40 -60L/min of NH ₃ , 200-300 sccm of TMGa, and 20-50 sccm of SiH ₄ , grow a Si-doped N-type GaN layer with a thickness of 2μm-4μm, and the Si doping concentration is 5×10 ¹⁸ atoms/ cm ³ -1×10 ¹⁹ atoms/cm ³ .

Step 23: growing the active layer MQW in the MOCVD reaction chamber.

The active layer MQW includes: alternately grown In _x Ga _(1-x) N well layers and GaN barrier layers, and the alternating period is controlled at 10-15.

Specifically, at a temperature of 700°C-750°C and a reaction chamber pressure of 300mbar-400mbar, 50-90L/min of N ₂ , 40-60L/min of NH ₃ , 10-50sccm of TMGa, 1000-2000sccm of Under the condition of TMIn, the In _x Ga _(1-x) N well layer with a thickness of 3nm-4nm is grown, wherein,

x=0.15-0.25,

In doping concentration is 1×10 ²⁰ atoms/cm ³ -3×10 ²⁰ atoms/cm ³ .

Specifically, at a temperature of 800°C-850°C, 50-90 L/min of N ₂ , 40-60 L/min of NH ₃ , and 10-50 sccm of TMGa are fed into the conditions, and the thickness of 10 nm-15 nm is grown. GaN barrier layer.

Step 24: growing a P-type AlGaN layer in the MOCVD reaction chamber.

Specifically, under the conditions of a temperature of 850-950°C, a reaction chamber pressure of 200r-400mbar, 50-90L/min of N ₂ , 40-60L/min of NH ₃ , and 50-100sccm of TMGa, the growth of Mg The P-type AlGaN layer is doped. The thickness of the Mg-doped P-type AlGaN layer is 50nm-100nm; wherein, the Al doping concentration is 1×10 ²⁰ atoms/cm ³ -3×10 ²⁰ atoms/cm ³ ; the Mg doping concentration is 5×10 ¹⁸ atoms/cm ³ -1×10 ¹⁹ atoms/cm ³ .

Step 25: P-type GaN layer in the MOCVD reaction chamber.

Specifically, under the condition that the high temperature is 950°C-1000°C, the reaction chamber pressure is 200-600mbar, and 50-90L/min of _N2 , 40-60L/min of _NH3 , and 50-100sccm of TMGa are fed, The P-type GaN layer doped with Mg is grown. The thickness of the P-type GaN layer doped with Mg is 100nm-300nm, wherein the Mg doping concentration is 1×10 ¹⁹ atoms/cm ³ -1×10 ²⁰ atoms/cm ³ .

Step 26: Under the condition that the temperature is 700°C-800°C and 100L/min-150L/min of N ₂ is fed, keep it warm for 20-30min, and cool with the furnace.

The LED epitaxial buffer layer growth method provided by the present invention, by utilizing the magnetron sputtering method to grow high-quality MgZnO thin film on the sapphire substrate as buffer layer, utilizes MgZnO material Zn ²⁺ (0.060nm) and Mg ²⁺ (0.057nm ) ionic radius is close, Zn ²⁺ (0.060nm) and Mg ²⁺ replace each other in the oxide lattice to form MgZnO, the lattice distortion caused by this substitutional mixed crystal is small, between MgZnO and GaN and MgZnO The state of complete relaxation between the sapphire substrate and the sapphire substrate is achieved, the stress caused by lattice mismatch is basically eliminated, the defects such as dislocations generated during material growth are greatly reduced, the wave function overlap of electrons and holes increases, and the electrons and holes The recombination efficiency of holes increases, and the number of photons generated by recombination per unit time increases, thereby improving the luminous efficiency of the LED.

In addition, the MgZnO material has a wider adjustable bandgap range (3.3-7.8ev), which increases the effective barrier height of the quantum barrier, effectively confines and blocks electrons from overflowing from the quantum well, and suppresses the generation of electron leakage current. , thereby improving the injection efficiency of electrons and holes in the quantum well, and improving the luminous efficiency of the LED.

comparative example

Fig. 3 is a schematic structural diagram of LED epitaxy prepared by a traditional LED epitaxy growth method. 3, the LED epitaxy includes: a buffer layer 302, an N-type GaN layer 303, an active layer MQW304, a P-type AlGaN layer 305, and a P-type GaN layer 306 grown sequentially on a sapphire substrate 301; The layer 302 includes: a low-temperature GaN buffer layer 3021, a 3D GaN layer 3022, and a 2D GaN layer 3023; an active layer MQW304, including alternately grown In _x Ga _(1-x) N well layers 3041 and GaN barrier layers 3042, Alternate cycle control in 10-15.

Using MOCVD to grow LED epitaxy on sapphire substrates, the traditional method includes:

Step 31: Treat the sapphire substrate for 5min-10min at a temperature of 900°C-1100°C, a reaction chamber pressure of 100-200mbar, and 50-100L/min of H ₂ .

Step 32: growing a low-temperature GaN buffer layer.

Specifically, under the conditions of a temperature of 550-650°C, a reaction chamber pressure of 300-600mbar, 50-90L/min of H ₂ , 40-60L/min of NH ₃ , and 50-100sccm of TMGa, the sapphire A low-temperature buffer layer GaN with a thickness of 30nm-60nm is grown on the substrate.

Step 33: growing a 3D GaN layer.

Specifically, under the conditions of a temperature of 850-1000°C, a reaction chamber pressure of 300-600mbar, 50-90L/min of H ₂ , 40-60L/min of NH ₃ , and 200-300sccm of TMGa, the continuous growth 2μm-3μm 3D GaN layer.

Step 34: Growing a 2D GaN layer.

Specifically, under the conditions of a temperature of 1000-1100°C, a reaction chamber pressure of 300-600mbar, 50-90L/min of H ₂ , 40-60L/min of NH ₃ , and 300-400sccm of TMGa, the continuous growth 2D GaN layer of 2μm-3μm.

Step 35: growing a Si-doped N-type GaN layer.

Specifically, at a temperature of 1000°C-1100°C and a reaction chamber pressure of 150-300mbar, 50-90L/min of H ₂ , 40-60L/min of NH ₃ , 200-300sccm of TMGa, 20-50sccm of Under the condition of SiH ₄ , a 2 μm-4 μm thick Si-doped N-type GaN layer is grown, and the Si doping concentration is 5×10 ¹⁸ atoms/cm ³ -1×10 ¹⁹ atoms/cm ³ .

Step 36: Periodically grow the active layer MQW.

The active layer MQW includes: alternately grown In _x Ga _(1-x) N well layers and GaN barrier layers, and the alternating period is controlled at 10-15.

Specifically, at a temperature of 700°C-750°C and a reaction chamber pressure of 300mbar-400mbar, 50-90L/min of N ₂ , 40-60L/min of NH ₃ , 10-50sccm of TMGa, 1000-2000sccm of Under the condition of TMIn, the In _x Ga _(1-x) N well layer with a thickness of 3nm-4nm is grown, wherein,

x=0.15-0.25,

In doping concentration is 1×10 ²⁰ atoms/cm ³ -3×10 ²⁰ atoms/cm ³ .

Specifically, at a temperature of 800°C-850°C, 50-90 L/min of N ₂ , 40-60 L/min of NH ₃ , and 10-50 sccm of TMGa are fed into the conditions, and the thickness of 10 nm-15 nm is grown. GaN barrier layer.

Step 37: growing a P-type AlGaN layer.

Specifically, under the conditions of a temperature of 850-950°C, a reaction chamber pressure of 200r-400mbar, 50-90L/min of N ₂ , 40-60L/min of NH ₃ , and 50-100sccm of TMGa, the growth of Mg The P-type AlGaN layer is doped. The thickness of the Mg-doped P-type AlGaN layer is 50nm-100nm; wherein, the Al doping concentration is 1×10 ²⁰ atoms/cm ³ -3×10 ²⁰ atoms/cm ³ ; the Mg doping concentration is 5×10 ¹⁸ atoms/cm ³ -1×10 ¹⁹ atoms/cm ³ .

Step 38: growing a P-type GaN layer.

Specifically, under the condition that the high temperature is 950°C-1000°C, the reaction chamber pressure is 200-600mbar, and 50-90L/min of _N2 , 40-60L/min of _NH3 , and 50-100sccm of TMGa are fed, The P-type GaN layer doped with Mg is grown. The thickness of the P-type GaN layer doped with Mg is 100nm-300nm, wherein the Mg doping concentration is 1×10 ¹⁹ atoms/cm ³ -1×10 ²⁰ atoms/cm ³ .

Step 309: Under the condition that the temperature is 700°C-800°C and 100L/min-150L/min of N ₂ is fed, keep the temperature for 20-30min, and cool down with the furnace.

Prepare 4 pieces of sample 1 according to the traditional LED growth method, and prepare 4 pieces of sample 2 according to the method provided by this patent; after the sample is grown, take it out and test the XRD102 surface of the epitaxial wafer 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. Conduct photoelectric performance test: test the photoelectric performance of sample 1 and sample 2 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

As can be seen from Table 1, the XRD102 surface value of the sample (sample 2) produced by the method provided by the present invention becomes smaller, indicating that the sample material produced by the method provided by the present invention has fewer material defects, and the crystal quality of the epitaxial layer is obviously improved.

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

It can be seen from Table 2 that the sample LED produced by the method provided by the present invention has high brightness and good antistatic ability, which is due to the method provided by the present invention reducing LED epitaxial growth defects, increasing the recombination efficiency of electrons and holes, and improving Luminous efficiency of LEDs.

Compared with the prior art, the LED epitaxial buffer layer growth method described in this application achieves the following effects:

The LED epitaxial buffer layer growth method provided by the present invention, by utilizing the magnetron sputtering method to grow high-quality MgZnO thin film on the sapphire substrate as buffer layer, utilizes MgZnO material Zn ²⁺ (0.060nm) and Mg ²⁺ (0.057nm ) ionic radius is close, Zn ²⁺ (0.060nm) and Mg ²⁺ replace each other in the oxide lattice to form MgZnO, the lattice distortion caused by this substitutional mixed crystal is small, between MgZnO and GaN and MgZnO The state of complete relaxation between the sapphire substrate and the sapphire substrate is achieved, the stress caused by lattice mismatch is basically eliminated, the defects such as dislocations generated during material growth are greatly reduced, the wave function overlap of electrons and holes increases, and the electrons and holes The recombination efficiency of holes increases, and the number of photons generated by recombination per unit time increases, thereby improving the luminous efficiency of the LED.

In addition, the MgZnO material has a wider adjustable bandgap range (3.3-7.8ev), which increases the effective barrier height of the quantum barrier, effectively confines and blocks electrons from overflowing from the quantum well, and suppresses the generation of electron leakage current. , thereby improving the injection efficiency of electrons and holes in the quantum well, and improving the luminous efficiency of the LED.

Since the method part has already described the embodiment of the present application in detail, the expanded description of the corresponding part of the structure and method involved in the embodiment is omitted here, and will not be repeated here. For the description of the specific content in the structure, reference may be made to the content of the method embodiment, which is not specifically limited here.

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 forms disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various Various other combinations, modifications and environments, and can be modified by the above teachings or the technology or knowledge in the related field within the scope of the application concept described herein. 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 (10)

1. A growth method of an LED epitaxial buffer layer is characterized by sequentially comprising the following steps:

selecting high-purity (99.999%) ZnO and MgO powders, mixing the ZnO and MgO powders according to the proportion of 1:1-1:1.2, compacting in a die of a 130-150MPa hydraulic press, and then burning in the air for 8-10h to obtain the MgZnO high-purity alloy ceramic target;

putting a sapphire substrate into a magnetron sputtering reaction chamber, using the MgZnO high-purity alloy ceramic target as a target material, wherein the distance between the target material and the sapphire substrate is 7-10cm, the chamber temperature is 150-250 ℃, the reaction chamber pressure is 1-1.5Pa, the radio frequency power is 100-140W, introducing 10-40sccm oxygen and 70-280sccm argon, and growing a 150-200nm thick MgZnO film on the sapphire substrate under the conditions that the flow rate ratio of the oxygen to the argon is controlled to be 1:7, wherein the growth time is 15-20 min;

putting the sapphire substrate on which the MgZnO film grows into an MOCVD reaction chamber, and growing an N-type GaN layer, an active layer MQW, a P-type AlGaN layer and a P-type GaN layer which are doped with Si in sequence;

introducing N of 100L/min-150L/min at the temperature of 700-800 DEG C₂Keeping the temperature for 20-30min under the condition of (1), and cooling along with the furnace.

2. The LED epitaxial buffer layer growth method of claim 1,

introducing 50-90L/min H at the temperature of 1000-1100 ℃ and the pressure of a reaction cavity of 150-300mbar₂40-60L/min NH₃200-300sccm TMGa and 20-50sccm SiH₄Under the conditions of (1), growing a Si-doped N-type GaN layer with a thickness of 2-4 μm and a Si doping concentration of 5X 10¹⁸atoms/cm³-1×10¹⁹atoms/cm³。

3. The LED epitaxial buffer layer growth method of claim 1,

introducing 50-100L/min H at 900-1100 deg.C and reaction cavity pressure of 100-200mbar₂Processing the sapphire substrate for 5-10 min under the condition (1).

4. The LED epitaxial buffer layer growth method of claim 1,

the active layer MQW comprises: alternatively grown In_xGa_(1-x)The N well layer and the GaN barrier layer are controlled to be 10-15 in alternating period.

5. The LED epitaxial buffer layer growth method of claim 4,

at a temperature of 700 deg.CAt the temperature of-750 ℃, the pressure of a reaction cavity is 300mbar-400mbar, and 50-90L/min N is introduced₂40-60L/min NH₃Growing the In with the thickness of 3nm to 4nm under the conditions of TMGa of 10 to 50sccm and TMIn of 1000-2000sccm_xGa_(1-x)An N-well layer, wherein,

x＝0.15-0.25，

in doping concentration of 1 × 10²⁰atoms/cm³-3×10²⁰atoms/cm³。

6. The LED epitaxial buffer layer growth method of claim 4,

introducing 50-90L/min N at 800-850 deg.C₂40-60L/min NH₃And growing the GaN barrier layer with the thickness of 10nm-15nm under the condition of TMGa of 10-50 sccm.

7. The LED epitaxial buffer layer growth method of claim 1,

introducing 50-90L/min N at the temperature of 850 ℃ and 950 ℃ and the pressure of a reaction cavity of 200r-400mbar₂40-60L/min NH₃And growing the P-type AlGaN layer doped with Mg under the condition of TMGa of 50-100 sccm.

8. The LED epitaxial buffer layer growth method of claim 7,

the thickness of the Mg-doped P-type AlGaN layer is 50nm-100 nm; wherein,

al doping concentration of 1X 10²⁰atoms/cm³-3×10²⁰atoms/cm³；

Mg doping concentration of 5 x 10¹⁸atoms/cm³-1×10¹⁹atoms/cm³。

9. The LED epitaxial buffer layer growth method of claim 1,

introducing 50-90L/min at the high temperature of 950-1000 ℃ and the reaction cavity pressure of 200-600mbarN₂40-60L/min NH₃And growing the P-type GaN layer doped with Mg under the condition of TMGa of 50-100 sccm.

10. The LED epitaxial buffer layer growth method of claim 9,

the thickness of the Mg-doped P-type GaN layer is 100nm-300nm, wherein,

mg doping concentration is 1X 10¹⁹atoms/cm³-1×10²⁰atoms/cm³。