CN109473511B - A kind of gallium nitride-based light-emitting diode epitaxial wafer and its growth method - Google Patents

Abstract

The invention discloses a gallium nitride-based light-emitting diode epitaxial wafer and a growth method thereof, belonging to the technical field of semiconductors. The growth method includes: providing a substrate; growing an N-type semiconductor layer on the substrate; growing an active layer on the N-type semiconductor layer; in a growth atmosphere formed of hydrogen, in the active layer A first P-type semiconductor layer is grown on the layer; in a growth atmosphere formed of nitrogen, a second P-type semiconductor layer is grown on the first P-type semiconductor layer; wherein the first P-type semiconductor layer and the The second P-type semiconductor layers each include a plurality of magnesium nitride layers and a plurality of magnesium-doped gallium nitride layers, and the plurality of magnesium nitride layers and the plurality of magnesium-doped gallium nitride layers are alternately stacked. . The invention can increase the hole concentration in the P-type semiconductor layer, and finally improve the luminous efficiency of the LED.

Description

A kind of gallium nitride-based light-emitting diode epitaxial wafer and its growth method

technical field

The invention relates to the technical field of semiconductors, in particular to a gallium nitride-based light-emitting diode epitaxial wafer and a growth method thereof.

Background technique

Light Emitting Diode (English: Light Emitting Diode, LED for short) is a semiconductor electronic component that can emit light. With the rapid development of the LED industry, LEDs are widely used in traffic lights, street lights, landscape lights, lighting, backlights and other fields, and the requirements for LED brightness are getting higher and higher. Epitaxial wafers are the primary products in the LED manufacturing process. Many LED experts and scholars adjust the structure of the epitaxial wafers to improve the brightness of LEDs.

Gallium nitride (GaN) has good thermal conductivity, high temperature resistance, acid and alkali resistance, high hardness and other excellent characteristics, so that gallium nitride (GaN)-based LEDs have received more and more attention and research. The existing gallium nitride-based LED includes a substrate, an N-type semiconductor layer, an active layer and a P-type semiconductor layer, and the N-type semiconductor layer, the active layer and the P-type semiconductor layer are sequentially stacked on the substrate. The P-type semiconductor layer is used to provide holes for recombination emission, the N-type semiconductor layer is used to provide electrons for recombination emission, the active layer is used for radiative recombination emission of electrons and holes, and the substrate is used to provide epitaxial materials growth surface.

In the process of realizing the present invention, the inventor found that the prior art has at least the following problems:

Since the radii of magnesium atoms and gallium atoms are similar in size, substitution atoms are easily formed, so the P-type semiconductor layer usually adopts magnesium-doped gallium nitride. Theoretically, the doping concentration of magnesium in the P-type semiconductor layer is positively correlated with the concentration of free holes in the P-type semiconductor layer. If the doping concentration of magnesium in the P-type semiconductor layer is low, the concentration of free holes in the P-type semiconductor layer will be low, which will limit the recombination of electrons and holes in the active layer, resulting in low luminous efficiency of the LED. . Therefore, the doping concentration of magnesium in the P-type semiconductor layer is usually high.

The high doping concentration of magnesium element will bring about the problem of magnesium compensation. It is easy to form a neutral complex in the P-type semiconductor layer, which reduces the activation efficiency of magnesium and produces a large number of point defects, resulting in the crystal of the P-type semiconductor layer. The quality is poor, which affects the concentration of free holes in the P-type semiconductor layer and limits the recombination of electrons and holes in the active layer, resulting in low luminous efficiency of the LED. That is, the luminous efficiency of the LED is restricted by the crystal quality of the P-type semiconductor layer and the activation efficiency of magnesium atoms in the P-type semiconductor layer.

However, the P-type semiconductor layer is generally grown in a growth atmosphere formed of a mixed gas of nitrogen and hydrogen. Hydrogen atoms in hydrogen will form Mg-H bonds with magnesium atoms, resulting in low activation efficiency of magnesium; at the same time, the crystal quality of the P-type semiconductor layer is poor in the growth atmosphere of nitrogen. Therefore, the concentration of free holes in the P-type semiconductor layer is low, which seriously affects the luminous efficiency of the LED.

SUMMARY OF THE INVENTION

The embodiments of the present invention provide a gallium nitride-based light emitting diode epitaxial wafer and a growth method thereof, which can solve the problem that the concentration of free holes in the P-type semiconductor layer in the prior art is low, resulting in low luminous efficiency of the LED. The technical solution is as follows:

In one aspect, an embodiment of the present invention provides a method for growing a gallium nitride-based light-emitting diode epitaxial wafer, the growth method comprising:

providing a substrate;

growing an N-type semiconductor layer on the substrate;

growing an active layer on the N-type semiconductor layer;

growing a first P-type semiconductor layer on the active layer in a growth atmosphere formed of hydrogen;

growing a second P-type semiconductor layer on the first P-type semiconductor layer in a growth atmosphere formed of nitrogen;

Wherein, the first P-type semiconductor layer and the second P-type semiconductor layer each include a plurality of magnesium nitride layers and a plurality of magnesium-doped gallium nitride layers, and the plurality of magnesium nitride layers and the A plurality of magnesium-doped gallium nitride layers are alternately stacked.

Optionally, the number of magnesium nitride layers in the first P-type semiconductor layer is the same as the number of magnesium-doped gallium nitride layers in the first P-type semiconductor layer; The number of magnesium nitride layers is 5 to 10.

Optionally, the number of magnesium nitride layers in the second P-type semiconductor layer is the same as the number of magnesium-doped gallium nitride layers in the second P-type semiconductor layer; The number of magnesium nitride layers is 5 to 10.

Optionally, the thickness of the magnesium nitride layer is 1 nm˜3 nm.

Optionally, the thickness of the magnesium-doped gallium nitride layer is 4 nm˜7 nm.

Optionally, the doping concentration of magnesium in the magnesium-doped gallium nitride layer is 10 ²⁰ cm ^-3 to 3*10 ²⁰ cm ^-3 .

Optionally, the sum of the thicknesses of the second P-type semiconductor layer and the first P-type semiconductor layer is 100 nm˜200 nm.

Optionally, the growth conditions of the first P-type semiconductor layer are the same as the growth conditions of the second P-type semiconductor layer, and the growth conditions include growth temperature and growth pressure.

Preferably, the growth temperature of the first P-type semiconductor layer is 800° C.˜1000° C., and the growth pressure of the first P-type semiconductor layer is 200 torr˜600 torr.

On the other hand, an embodiment of the present invention provides a gallium nitride-based light-emitting diode epitaxial wafer, the gallium nitride-based light-emitting diode epitaxial wafer includes a substrate, an N-type semiconductor layer, an active layer, and a first P-type semiconductor layer and a second P-type semiconductor layer, the N-type semiconductor layer, the active layer, the first P-type semiconductor layer and the second P-type semiconductor layer are sequentially stacked on the substrate, the first A P-type semiconductor layer is grown in a growth atmosphere formed of hydrogen gas, the second P-type semiconductor layer is grown in a growth atmosphere formed of nitrogen; the first P-type semiconductor layer and the second P-type semiconductor layer are grown Each includes a plurality of magnesium nitride layers and a plurality of magnesium-doped gallium nitride layers, and the plurality of magnesium nitride layers and the plurality of magnesium-doped gallium nitride layers are alternately stacked.

The beneficial effects brought by the technical solutions provided in the embodiments of the present invention are:

By first growing the first P-type semiconductor layer in the growth atmosphere formed by hydrogen, the hydrogen has an etching effect, and the first P-type semiconductor layer can be processed, effectively covering the defects extending to the P-type semiconductor layer during the epitaxial growth process, The crystal quality of the P-type semiconductor layer is greatly improved; the second P-type semiconductor layer is grown in the growth atmosphere formed by nitrogen, which can avoid the formation of Mg-H bonds between hydrogen atoms and magnesium atoms in the growth atmosphere formed by hydrogen, which is equivalent to The doping amount of magnesium in the P-type semiconductor layer is increased, that is, the activation efficiency of magnesium in the P-type semiconductor layer is improved. The first P-type semiconductor layer and the second P-type semiconductor layer respectively improve the P-type semiconductor layer from the crystal quality of the P-type semiconductor layer and the activation efficiency of magnesium atoms in the P-type semiconductor layer, which can effectively improve the P-type semiconductor layer. The hole concentration in the type semiconductor layer will ultimately improve the luminous efficiency of the LED. Moreover, both the first P-type semiconductor layer and the second P-type semiconductor layer include a plurality of magnesium nitride layers and a plurality of magnesium-doped gallium nitride layers that are alternately stacked, and the magnesium atoms form substitution atoms in the gallium nitride, It can be effectively doped in the P-type semiconductor layer to increase the proportion of magnesium atoms in the gallium position, while reducing the filling type of magnesium atoms, avoiding the presence of magnesium atoms in the P-type semiconductor layer in the form of impurities, and improving the P-type semiconductor layer. The crystal quality further improves the luminous efficiency of the LED.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a flowchart of a method for growing a GaN-based light-emitting diode epitaxial wafer provided by an embodiment of the present invention;

2 is a schematic structural diagram of a gallium nitride-based light-emitting diode epitaxial wafer provided by an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a first P-type semiconductor layer and a second P-type semiconductor layer provided by an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

Embodiments of the present invention provide a method for growing a gallium nitride-based light-emitting diode epitaxial wafer. FIG. 1 is a flowchart of a method for growing a GaN-based light-emitting diode epitaxial wafer according to an embodiment of the present invention. Referring to Figure 1, the growth method includes:

Step 101: Provide a substrate.

Specifically, the material of the substrate can be sapphire (the main material is aluminum oxide), such as sapphire with a crystal orientation of [0001].

Specifically, this step 101 may include:

The temperature is controlled to be 1000°C to 1200°C (preferably 1100°C), and the substrate is annealed for 1 minute to 10 minutes (preferably 5 minutes) in a hydrogen atmosphere;

The substrate is nitrided.

The above steps are used to clean the surface of the substrate to avoid doping impurities into the epitaxial wafer, which is beneficial to improve the growth quality of the epitaxial wafer.

Step 102: growing an N-type semiconductor layer on the substrate.

Specifically, the material of the N-type semiconductor layer can be N-type doped (eg, silicon) gallium nitride.

Further, the thickness of the N-type semiconductor layer may be 1 μm˜5 μm, preferably 3 μm; the doping concentration of the N-type dopant in the N-type semiconductor layer may be 10 ¹⁸ cm ^-3 -10 ¹⁹ cm ^-3 , preferably 5 *10 ¹⁸ cm ^-3 .

Specifically, this step 102 may include:

The temperature is controlled to be 1000°C to 1200°C (preferably 1100°C), the pressure is controlled to be 100torr to 500torr (preferably 300torr), and an N-type semiconductor layer is grown on the substrate.

Optionally, before step 102, the preparation method may include:

A buffer layer is formed on the substrate by using a physical vapor deposition (English: Physical Vapor Deposition, PVD for short) technology.

Accordingly, the N-type semiconductor layer is grown on the buffer layer.

The stress and defects caused by lattice mismatch between the substrate material and the gallium nitride are relieved by arranging the buffer layer, and a nucleation center is provided for the epitaxial growth of the gallium nitride material.

Specifically, the material of the buffer layer can be aluminum nitride or aluminum gallium nitride.

Specifically, using PVD technology to form a buffer layer on the substrate may include:

The temperature is controlled to be 400°C to 800°C (preferably 600°C), the pressure is 4torr to 6torr (preferably 5torr), the sputtering power is 3000W to 5000W (preferably 4000W), and the magnetron sputtering technology is used to form the substrate on the substrate. The buffer layer.

Preferably, after the buffer layer is formed on the substrate using PVD technology, the preparation method may further include:

The undoped gallium nitride layer is grown on the buffer layer using MOCVD technology.

Accordingly, the N-type semiconductor layer is grown on the undoped gallium nitride layer.

The stress and defects caused by lattice mismatch between the substrate material and the gallium nitride are further relieved by providing the undoped gallium nitride layer, and a growth surface with better crystal quality is provided for the main structure of the epitaxial wafer.

In the specific implementation, firstly, the vertical growth of gallium nitride is carried out on the buffer layer, and multiple independent three-dimensional island-like structures will be formed, which are called three-dimensional nucleation layers; then, on all three-dimensional island-like structures and each three-dimensional island-like structure The lateral growth of gallium nitride is carried out between them to form a two-dimensional planar structure, which is called a two-dimensional recovery layer; finally, a thicker layer of gallium nitride is grown on the two-dimensional growth layer at a high temperature, which is called an intrinsic gallium nitride layer. In this embodiment, the three-dimensional nucleation layer, the two-dimensional recovery layer and the intrinsic gallium nitride layer are collectively referred to as the undoped gallium nitride layer.

Further, the thickness of the undoped gallium nitride layer may be 1 μm˜5 μm, preferably 3 μm.

Specifically, using MOCVD technology to grow an undoped gallium nitride layer on the buffer layer may include:

The temperature is controlled to be 1000°C to 1100°C (preferably 1050°C), the pressure is controlled to be 100torr to 500torr (preferably 300torr), and an undoped gallium nitride layer is grown on the buffer layer.

Step 103: growing an active layer on the N-type semiconductor layer.

Specifically, the active layer may include multiple quantum wells and multiple quantum barriers, and multiple quantum wells and multiple quantum barriers are alternately stacked; the material of the quantum wells may be indium gallium nitride (InGaN), such as In _x Ga _{1 -x} N, 0<x<1, the material of the quantum barrier can be gallium nitride.

Further, the thickness of the quantum wells can be 2nm to 3nm, preferably 2.5nm; the thickness of the quantum barriers can be 9nm to 20nm, preferably 15nm; the number of quantum wells is the same as the number of quantum barriers, and the number of quantum barriers can be 5 1 to 11, preferably 8.

Specifically, this step 103 may include:

The active layer is grown on the N-type semiconductor layer; wherein, the growth temperature of the quantum well is 720°C to 829°C (preferably 760°C), and the pressure is 100torr to 500torr (preferably 300torr); the growth temperature of the quantum barrier is 850°C ~959°C (preferably 900°C), and the pressure is 100torr to 500torr (preferably 300torr).

Optionally, before step 103, the preparation method may include:

The stress relief layer is grown on the N-type semiconductor layer by using MOCVD technology.

Accordingly, the active layer is grown on the stress release layer.

By setting the stress release layer, the stress caused by the lattice mismatch between sapphire and gallium nitride is released, and the crystal quality of the active layer is improved, which is conducive to the radiative recombination of electrons and holes in the active layer, and improves the internal performance of the LED. Quantum efficiency, thereby improving the luminous efficiency of LEDs.

Specifically, the material of the stress release layer can be gallium indium aluminum nitride (AlInGaN), which can effectively release the stress caused by the lattice mismatch between sapphire and gallium nitride, improve the crystal quality of the epitaxial wafer, and improve the luminous efficiency of the LED.

Preferably, the molar content of the aluminum component in the stress release layer may be less than or equal to 0.2, and the molar content of the indium component in the stress release layer may be less than or equal to 0.05 to avoid adverse effects.

Further, the thickness of the stress release layer may be 50 nm to 500 nm, preferably 300 nm.

Specifically, using the MOCVD technology to grow the stress release layer on the N-type semiconductor layer may include:

The temperature is controlled to be 800°C to 1100°C (preferably 950°C), and the pressure is controlled to be 100torr to 500torr (preferably 300torr), and a stress release layer is grown on the N-type semiconductor layer.

Step 104 : growing a first P-type semiconductor layer on the active layer in a growth atmosphere formed of hydrogen gas.

Step 105: A second P-type semiconductor layer is grown on the first P-type semiconductor layer in a growth atmosphere formed of nitrogen.

Wherein, both the first P-type semiconductor layer and the second P-type semiconductor layer include a plurality of magnesium nitride layers and a plurality of magnesium-doped gallium nitride layers, a plurality of magnesium nitride layers and a plurality of magnesium-doped nitride layers The gallium layers are alternately stacked.

In the embodiment of the present invention, the first P-type semiconductor layer is first grown in a growth atmosphere formed by hydrogen, and the hydrogen has an etching effect, so that the first P-type semiconductor layer can be processed, effectively covering the extension to the P-type semiconductor during the epitaxial growth process. The defects of the layer can greatly improve the crystal quality of the P-type semiconductor layer; then growing the second P-type semiconductor layer in the growth atmosphere formed by nitrogen can avoid the formation of Mg-H by hydrogen atoms and magnesium atoms in the growth atmosphere formed by hydrogen bond, which is equivalent to increasing the doping amount of magnesium in the P-type semiconductor layer, that is, improving the activation efficiency of magnesium in the P-type semiconductor layer. The first P-type semiconductor layer and the second P-type semiconductor layer respectively improve the P-type semiconductor layer from the crystal quality of the P-type semiconductor layer and the activation efficiency of magnesium atoms in the P-type semiconductor layer, which can effectively improve the P-type semiconductor layer. The hole concentration in the type semiconductor layer will ultimately improve the luminous efficiency of the LED. Moreover, both the first P-type semiconductor layer and the second P-type semiconductor layer include a plurality of magnesium nitride layers and a plurality of magnesium-doped gallium nitride layers that are alternately stacked, and the magnesium atoms form substitution atoms in the gallium nitride, It can be effectively doped in the P-type semiconductor layer to increase the proportion of magnesium atoms in the gallium position, while reducing the filling type of magnesium atoms, avoiding the presence of magnesium atoms in the P-type semiconductor layer in the form of impurities, and improving the P-type semiconductor layer. The crystal quality further improves the luminous efficiency of the LED.

Optionally, the number of magnesium nitride layers in the first P-type semiconductor layer is the same as the number of magnesium-doped gallium nitride layers in the first P-type semiconductor layer; the number of magnesium nitride layers in the first P-type semiconductor layer It may be 5 to 10, preferably 8.

If the number of magnesium nitride layers and magnesium-doped gallium nitride layers in the first P-type semiconductor is less than 5, it may be due to the number of magnesium nitride layers and magnesium-doped gallium nitride layers in the first P-type semiconductor It is too small to effectively improve the crystal quality of the P-type semiconductor layer; if the number of magnesium nitride layers and magnesium-doped gallium nitride layers in the first P-type semiconductor is greater than 10, the thickness of the P-type semiconductor may be thicker , The P-type semiconductor layer absorbs light seriously, which affects the light-emitting efficiency of the LED.

Optionally, the number of magnesium nitride layers in the second P-type semiconductor layer is the same as the number of magnesium-doped gallium nitride layers in the second P-type semiconductor layer; the number of magnesium nitride layers in the second P-type semiconductor layer It may be 5 to 10, preferably 8.

If the number of magnesium nitride layers and magnesium-doped gallium nitride layers in the second P-type semiconductor is less than 5, it may be due to the number of magnesium nitride layers and magnesium-doped gallium nitride layers in the second P-type semiconductor It is too small to effectively improve the crystal quality of the P-type semiconductor layer; if the number of the magnesium nitride layer and the magnesium-doped gallium nitride layer in the second P-type semiconductor is greater than 10, it may be due to the nitrogen in the second P-type semiconductor. The number of magnesium oxide layers and magnesium-doped gallium nitride layers is large, which increases the complexity of the process and the implementation cost.

Optionally, the thickness of the magnesium nitride layer may be 1 nm˜3 nm, preferably 2 nm.

If the thickness of the magnesium nitride layer is less than 1 nm, the concentration of effective holes in the P-type semiconductor layer may not be effectively increased due to the thin magnesium nitride layer, resulting in an insignificant improvement in the luminous efficiency of the LED; If the thickness is greater than 3 nm, the crystal structure of the P-type semiconductor layer may be affected due to the thick magnesium nitride layer and excessive Mg.

Optionally, the thickness of the magnesium-doped gallium nitride layer may be 4 nm˜7 nm, preferably 5.5 nm.

If the thickness of the magnesium-doped gallium nitride layer is less than 4 nm, the crystal structure of the P-type semiconductor layer may be affected because the magnesium-doped gallium nitride layer is thinner; if the thickness of the magnesium-doped gallium nitride layer is greater than If the thickness of the Mg-doped gallium nitride layer is too thick, the coordination with the magnesium nitride layer may be affected, and the concentration of effective holes in the P-type semiconductor layer cannot be effectively increased, resulting in an insignificant improvement in the luminous efficiency of the LED.

Optionally, the doping concentration of magnesium in the magnesium-doped gallium nitride layer may be 10 ²⁰ cm ^-3 to 3*10 ²⁰ cm ^-3 , preferably 2*10 ²⁰ cm ^-3 .

If the doping concentration of magnesium in the magnesium-doped gallium nitride layer is less than 10 ²⁰ cm ^-3 , it may be caused by the small doping concentration of magnesium in the magnesium-doped gallium nitride layer and the magnesium nitride layer. The lattice mismatch between them reduces the crystal quality of the P-type semiconductor layer; if the doping concentration of magnesium in the magnesium-doped gallium nitride layer is greater than 3*10 ²⁰ cm ^-3 , it may be due to the nitrogen doped with magnesium. The doping concentration of magnesium element in the gallium nitride layer is relatively high, resulting in too many impurities in the P-type semiconductor layer, which reduces the crystal quality of the P-type semiconductor layer.

Optionally, the sum of the thicknesses of the first P-type semiconductor layer and the second P-type semiconductor layer may be 100 nm˜200 nm.

If the sum of the thicknesses of the first P-type semiconductor layer and the second P-type semiconductor layer is less than 100 nm, it may not be possible to provide the active layer due to the small sum of the thicknesses of the first P-type semiconductor layer and the second P-type semiconductor layer. A sufficient number of holes will affect the luminous efficiency of the LED; if the sum of the thicknesses of the first P-type semiconductor layer and the second P-type semiconductor layer is greater than 200 nm, the P-type semiconductor layer may be too thick, and the light absorption of the P-type semiconductor layer may occur. More serious, affecting the luminous efficiency of the LED.

Optionally, the growth conditions of the first P-type semiconductor layer and the growth conditions of the second P-type semiconductor layer may be the same, and the growth conditions include growth temperature and growth pressure. It is more convenient to use the same growth conditions.

Preferably, the growth temperature of the first P-type semiconductor layer may be 800° C.˜1000° C., and the growth pressure of the first P-type semiconductor layer may be 200torr˜600torr. According to the growth temperature and growth pressure, the quality of the formed P-type semiconductor layer is good.

Optionally, before step 104, the preparation method may further include:

The electron blocking layer is grown on the active layer using MOCVD technology.

Accordingly, the P-type semiconductor layer is grown on the electron blocking layer.

The luminous efficiency of the LED is reduced by disposing the electron blocking layer to prevent the electrons from transitioning to the hole providing layer for non-radiative recombination with the holes.

Specifically, the material of the electron blocking layer can be P-type doped aluminum gallium nitride (AlGaN), such as _{AlyGa1 -yN} , 0.1<y<0.5.

Further, the thickness of the electron blocking layer may be 20 nm to 100 nm, preferably 60 nm.

Specifically, using MOCVD technology to grow an electron blocking layer on the active layer may include:

The temperature is controlled to be 700°C to 1000°C (preferably 850°C), and the pressure is controlled to be 100torr to 500torr (preferably 300torr), and an electron blocking layer is grown on the active layer.

Preferably, before using the MOCVD technology to grow the electron blocking layer on the active layer, the preparation method may further include:

A low temperature P-type layer is grown on the active layer by MOCVD technology.

Accordingly, the electron blocking layer is grown on the low temperature P-type layer.

By setting the low temperature P-type layer, it is avoided that the high growth temperature of the electron blocking layer causes the precipitation of indium atoms in the active layer, which affects the luminous efficiency of the light emitting diode.

Specifically, the material of the low-temperature P-type layer may be P-type doped gallium nitride.

Further, the thickness of the low-temperature P-type layer may be 50 nm to 100 nm, preferably 75 nm; the doping concentration of the P-type dopant in the low-temperature P-type layer may be 10 ¹⁸ /cm ³ to 10 ²⁰ /cm ³ , preferably 10 ¹⁹ /cm ³ .

Specifically, using MOCVD technology to grow a low-temperature P-type layer on the active layer may include:

The temperature is controlled to be 600°C to 800°C (preferably 700°C), and the pressure is controlled to be 200torr to 500torr (preferably 350torr), and a low temperature P-type layer is grown on the active layer.

Optionally, after step 105, the preparation method may further include:

The contact layer is grown on the P-type semiconductor layer using MOCVD technology.

The contact layer is arranged to form an ohmic contact with the electrode or the transparent conductive film formed in the chip fabrication process.

Specifically, the material of the P-type contact layer may be P-type doped indium gallium nitride.

Further, the thickness of the P-type contact layer may be 5 nm to 100 nm, preferably 50 nm; the doping concentration of the P-type dopant in the P-type contact layer may be 10 ²¹ /cm ³ to 10 ²² /cm ³ , preferably 5 *10 ²¹ /cm ³ .

Specifically, the MOCVD technology is used to grow the contact layer on the P-type semiconductor layer, which may include:

The temperature is controlled to be 850°C to 1050°C (preferably 950°C), and the pressure is controlled to be 100torr to 300torr (preferably 200torr), and a contact layer is grown on the P-type semiconductor layer.

It should be noted that, after the above epitaxial growth is completed, the temperature is first lowered to 650°C to 850°C (preferably 750°C), and the epitaxial wafer is subjected to 5 minutes to 15 minutes (preferably 10 minutes) in a nitrogen atmosphere. Annealing treatment, and then the temperature of the epitaxial wafer is reduced to room temperature.

Controlling the temperature and pressure both refers to controlling the temperature and pressure in the reaction chamber for growing the epitaxial wafer, specifically the reaction chamber of the metal-organic chemical vapor deposition (English: Metal-organic Chemical Vapor Deposition, MOCVD for short) equipment. Trimethylgallium or triethylgallium is used as the gallium source, high-purity ammonia is used as the nitrogen source, trimethylindium is used as the indium source, trimethylaluminum is used as the aluminum source, the N-type dopant is silane, and the P-type dopant is used. The dopant is magnesium dimethylocene.

The embodiment of the present invention provides a gallium nitride-based light-emitting diode epitaxial wafer, which is suitable for growing by the growth method of the gallium nitride-based light-emitting diode epitaxial wafer shown in FIG. 1 . FIG. 2 is a schematic structural diagram of a gallium nitride-based light emitting diode epitaxial wafer according to an embodiment of the present invention. Referring to FIG. 2, the GaN-based light-emitting diode epitaxial wafer substrate 10, N-type semiconductor layer 20, active layer 30, first P-type semiconductor layer 41 and second P-type semiconductor layer 42, N-type semiconductor layer 20, The active layer 30 , the first P-type semiconductor layer 41 and the second P-type semiconductor layer 42 are sequentially stacked on the substrate 10 .

In this embodiment, the first P-type semiconductor layer 41 is grown in a growth atmosphere formed of hydrogen gas, and the second P-type semiconductor layer 42 is grown in a growth atmosphere formed of nitrogen gas. FIG. 3 is a schematic structural diagram of a first P-type semiconductor layer and a second P-type semiconductor layer according to an embodiment of the present invention. Referring to FIG. 3, the first P-type semiconductor layer 41 and the second P-type semiconductor layer 42 each include a plurality of magnesium nitride layers 43 and a plurality of magnesium-doped gallium nitride layers 44, a plurality of magnesium nitride layers 43 and a plurality of magnesium nitride layers 44. The magnesium-doped gallium nitride layers 44 are alternately stacked.

Optionally, as shown in FIG. 2 , the light-emitting diode epitaxial wafer may further include a buffer layer 51 , and the buffer layer 51 is disposed between the substrate 10 and the N-type semiconductor layer 20 .

Preferably, as shown in FIG. 2 , the light-emitting diode epitaxial wafer may further include an undoped gallium nitride layer 52 , and the undoped gallium nitride layer 52 is disposed between the buffer layer 51 and the N-type semiconductor layer 20 .

Optionally, as shown in FIG. 2 , the light emitting diode epitaxial wafer may further include a stress release layer 60 , and the stress release layer 60 is disposed between the N-type semiconductor layer 20 and the active layer 30 .

Optionally, as shown in FIG. 2 , the light emitting diode epitaxial wafer may further include an electron blocking layer 71 , and the electron blocking layer 71 is disposed between the active layer 30 and the first P-type semiconductor layer 41 .

Preferably, as shown in FIG. 2 , the light-emitting diode epitaxial wafer may further include a low-temperature P-type layer 72 , and the low-temperature P-type layer 72 is disposed between the active layer 30 and the electron blocking layer 71 .

Optionally, as shown in FIG. 2 , the light-emitting diode epitaxial wafer may further include a contact layer 80 , and the contact layer 80 is disposed on the second P-type semiconductor layer 42 .

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection of the present invention. within the range.

Claims (8)

1. A growth method of a gallium nitride-based light-emitting diode epitaxial wafer, wherein the growth method comprises: providing a substrate; growing an N-type semiconductor layer on the substrate; growing an active layer on the N-type semiconductor layer; growing a first P-type semiconductor layer on the active layer in a growth atmosphere formed of hydrogen; growing a second P-type semiconductor layer on the first P-type semiconductor layer in a growth atmosphere formed of nitrogen; Wherein, the first P-type semiconductor layer and the second P-type semiconductor layer each include a plurality of magnesium nitride layers and a plurality of magnesium-doped gallium nitride layers, and the plurality of magnesium nitride layers and the A plurality of magnesium-doped gallium nitride layers are alternately stacked; the doping concentration of magnesium in the magnesium-doped gallium nitride layers is 10 ²⁰ cm ^-3 to 3*10 ²⁰ cm ^-3 , and the second The growth conditions of the P-type semiconductor layer are the same as the growth conditions of the first P-type semiconductor layer, and the growth conditions include growth temperature and growth pressure. 2 . The growth method according to claim 1 , wherein the number of the magnesium nitride layers in the first P-type semiconductor layer is the same as that of the magnesium-doped gallium nitride layers in the first P-type semiconductor layer. 3 . The number is the same; the number of magnesium nitride layers in the first P-type semiconductor layer is 5-10. 3 . The growth method according to claim 1 , wherein the number of magnesium nitride layers in the second P-type semiconductor layer is the same as that of magnesium-doped gallium nitride in the second P-type semiconductor layer. 4 . The number of layers is the same; the number of magnesium nitride layers in the second P-type semiconductor layer is 5-10. 4 . The growth method according to claim 1 , wherein the thickness of the magnesium nitride layer is 1 nm˜3 nm. 5 . 5 . The growth method according to claim 1 , wherein the thickness of the magnesium-doped gallium nitride layer is 4 nm˜7 nm. 6 . 6 . The growth method according to claim 1 , wherein the sum of the thicknesses of the first P-type semiconductor layer and the second P-type semiconductor layer is 100 nm to 200 nm. 7 . 7 . The growth method according to claim 1 , wherein the growth temperature of the first P-type semiconductor layer is 800° C. to 1000° C., and the growth pressure of the first P-type semiconductor layer is 200 torr to 200 torr. 8 . 600torr. 8. A gallium nitride-based light-emitting diode epitaxial wafer, characterized in that the gallium-nitride-based light-emitting diode epitaxial wafer comprises a substrate, an N-type semiconductor layer, an active layer, a first P-type semiconductor layer and a second P-type semiconductor layer. type semiconductor layer, the N-type semiconductor layer, the active layer, the first P-type semiconductor layer and the second P-type semiconductor layer are sequentially stacked on the substrate, the first P-type semiconductor layer The layer is grown in a growth atmosphere formed of hydrogen, and the second P-type semiconductor layer is grown in a growth atmosphere formed of nitrogen; both the first P-type semiconductor layer and the second P-type semiconductor layer include a plurality of A magnesium nitride layer and a plurality of magnesium-doped gallium nitride layers, the plurality of magnesium nitride layers and the plurality of magnesium-doped gallium nitride layers are alternately stacked; the magnesium-doped gallium nitride The doping concentration of magnesium in the layer is 10 ²⁰ cm ^-3 to 3*10 ²⁰ cm ^-3 , and the growth conditions of the second P-type semiconductor layer are the same as the growth conditions of the first P-type semiconductor layer. Conditions include growth temperature and growth pressure.

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