CN106876538A - A kind of LED epitaxial growing method and light emitting diode - Google Patents

Abstract

The invention discloses a light-emitting diode epitaxial growth method, comprising: processing a sapphire substrate, growing a low-temperature buffer layer GaN, growing an undoped GaN layer, growing an N-type GaN layer doped with Si, growing a MgInAlN/SiGaN superlattice layer, Growing an In _x Ga _(1-x) N/GaN light-emitting layer, growing a P-type AlGaN layer, growing a P-type GaN layer doped with magnesium, and cooling down to obtain a light-emitting diode. The invention improves the luminous efficiency of the LED.

Description

A light-emitting diode epitaxial growth method and light-emitting diode

technical field

The present invention relates to the technical field of light-emitting diodes, and more specifically, to a light-emitting diode epitaxial growth method and a light-emitting diode.

Background technique

Light Emitting Diode (LED for short) is a solid-state lighting device, which is recognized by consumers for its advantages such as small size, low power consumption, long service life, high brightness, environmental protection, and durability. At present, the scale of domestic production of LEDs is also gradually expanding. With the improvement of people's living standards, the demand for improving the brightness and light efficiency of LEDs is increasing day by day. Good LED, which puts forward higher requirements for the production of LED. How to grow LEDs with better luminous efficiency has been paid more and more attention.

The LED epitaxial layer, as an important part of the LED, plays an extremely important role in the LED luminous efficiency, because the improvement of the crystal quality of the epitaxial layer can improve the performance of the LED device, thereby improving the luminous efficiency, life, and anti-aging of the LED. Ability, antistatic ability, stability.

The traditional LED structure includes the following epitaxial structure: substrate sapphire substrate, low-temperature buffer layer GaN layer, undoped GaN layer, Si-doped N-type GaN layer, light-emitting layer (made of In _x Ga _(1-x) N layer and GaN layer periodically grown), P-type AlGaN layer, Mg-doped P-type GaN layer, ITO layer, protective layer SiO ₂ layer, P electrode and N electrode.

In the Si-doped N-type GaN layer obtained by the epitaxial growth of the sapphire substrate, the traditional LED cannot block the speed of electron transmission. The electrons that are too fast are transported to the light-emitting layer and cause electron crowding, which makes the current distribution uneven and causes The resistance value of the N-type GaN layer becomes higher, which in turn causes the current in the LED to be consumed inside the light-emitting layer of the LED, thereby reducing the luminous efficiency of the LED.

Therefore, it is an urgent problem to be solved in this field to provide a solution for improving the epitaxial structure of the LED and improving the luminous efficiency of the LED.

Contents of the invention

In view of this, the present invention provides a light-emitting diode epitaxial growth method and a light-emitting diode, which solve the technical problem of reduced luminous efficiency caused by uneven current distribution in the LED epitaxial structure in the prior art.

In order to solve the above technical problems, the present invention proposes a light-emitting diode epitaxial growth method, including: processing the sapphire substrate, growing a low-temperature buffer layer GaN, growing an undoped GaN layer, growing an N-type GaN layer doped with Si, growing a MgInAlN/ SiGaN superlattice layer, growing In _x Ga _(1-x) N/GaN light-emitting layer, growing P-type AlGaN layer, growing magnesium-doped P-type GaN layer, and cooling to obtain a light-emitting diode; wherein,

growing the MgInAlN/SiGaN superlattice layer, further comprising:

In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000°C, and the flow rate is 50000-55000sccm of _NH3 , 50-70sccm of TMGa, 90-110L/min of _H2 , 1200-1400sccm of TMIn, 100- Under the conditions of 200sccm TMAl, 900-1000sccm Cp ₂ Mg, and 20-30sccm SiH ₄ , grow the MgInAlN/SiGaN superlattice layer:

In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000°C, and the flow rate is 50000-55000sccm of _NH3 , 100-200sccm of TMAl, 90-110L/min of _H2 , 1200-1400sccm of TMIn and 900- Under the condition of 1000sccm Cp ₂ Mg, grow a 4-7nm MgInAlN layer, wherein the In doping concentration is 3E19-4E19atom/cm ³ , and the Mg doping concentration is 1E19-1E20atom/cm ³ ;

In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000℃, and the flow rate is 50000-55000sccm _NH3 , 90-110L/min _H2 , 50-70sccm TMGa, 20-30sccm _SiH4 conditions Next, grow a SiGaN layer with a thickness of 8-15nm, wherein the Si doping concentration is 1E18-5E18atom/cm ³ ;

Periodically grow MgInAlN layers and SiGaN layers to obtain MgInAlN/SiGaN superlattice layers, wherein the growth period is 4-20;

The light-emitting diode obtained by cooling down further includes:

Cool down to 650-680°C and keep warm for 20-30 minutes, then turn off the heating system, turn off the gas supply system and cool down with the furnace to obtain light-emitting diodes.

Further, wherein, processing the sapphire substrate is:

In a hydrogen atmosphere at 1000-1100°C, 100L/min-130L/min of H ₂ is introduced, and the reaction chamber pressure is kept at 100-300mbar, and the sapphire substrate is processed for 5-10 minutes.

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

Under the conditions of a temperature of 500-600°C, a reaction chamber pressure of 300-600mbar, a flow rate of 10000-20000sccm of NH ₃ , 50-100sccm of TMGa and 100L/min-130L/min of _H2 , the sapphire substrate A low-temperature buffer layer GaN with a thickness of 20-40nm is grown on the bottom.

Further, wherein, the method also includes:

Raise the temperature to 1000-1100°C, keep the pressure of the reaction chamber at 300-600mbar, feed the flow rate of 30000-40000sccm of _NH3 and 100L/min-130L/min of _H2 , and keep the temperature stable for 300-500 seconds to etch the low-temperature buffer layer GaN into irregular island shapes.

Further, wherein, growing an undoped GaN layer is:

Under the conditions of a temperature of 1000-1200°C, a reaction chamber pressure of 300-600mbar, a flow rate of 30000-40000sccm of NH ₃ , 200-400sccm of TMGa and 100-130L/min of _H2 , the continuous growth thickness is 2 -4 μm undoped GaN layer.

Further, wherein, growing an N-type GaN layer doped with Si is:

In the reaction chamber, the pressure is 300-600mbar, the temperature is 1000-1200℃, the flow rate is 30000-60000sccm _NH3 , 200-400sccm TMGa, 100-130L/min _H2 and 20-50sccm _SiH4 conditions Next, continuously grow a Si-doped N-type GaN layer with a thickness of 3-4 μm, wherein the Si doping concentration is 5E18-1E19 atom/cm ³ .

Further, wherein, growing the In _x Ga _(1-x) N/GaN light-emitting layer is:

Under the condition of reaction chamber pressure of 300-400mbar, temperature of 700-750℃, flow rate of 50000-70000sccm of _NH3 , 20-40sccm of TMGa, 1500-2000sccm of TMIn and 100-130L/min of _N2 , growing an In-doped In _x Ga _(1-x) N layer (x=0.20-0.25) with a thickness of 2.5-3.5nm, and an emission wavelength of 450-455nm;

Raise the temperature to 750-850°C, under the condition that the reaction chamber pressure is 300-400mbar, the flow rate is 50000-70000sccm of _NH3 , 20-100sccm of TMGa and 100-130L/min of _N2 , the growth thickness is 8-15nm GaN layer;

The In _x Ga _(1-x) N/GaN light-emitting layer is obtained by periodically growing the In _x Ga _(1-x) N layer and the GaN layer alternately, wherein the number of growth cycles is 7-15.

Further, wherein, growing the P-type AlGaN layer is:

In the reaction chamber, the pressure is 200-400mbar, the temperature is 900-950°C, and the flow rate is 50000-70000sccm of _NH3 , 30-60sccm of TMGa, 100-130L/min of _H2 , 100-130sccm of TMAl and 1000- Under the condition of 1300sccm Cp ₂ Mg, a P-type AlGaN layer with a thickness of 50-100nm is continuously grown, wherein the Al doping concentration is 1E20-3E20atom/cm ³ , and the Mg doping concentration is 1E19-1E20atom/cm ³ .

Further, wherein, growing the p-type GaN layer doped with magnesium is:

In the reaction chamber, the pressure is 400-900mbar, the temperature is 950-1000℃, and the flow rate is 50000-70000sccm of _NH3 , 20-100sccm of TMGa, _100-130L /min of _H2 and 1000-3000sccm of Cp2Mg. Under the conditions, a magnesium-doped P-type GaN layer with a thickness of 50-200 nm is continuously grown, wherein the Mg doping concentration is 1E19-1E20 atom/cm ³ .

On the other hand, the present invention also provides a light-emitting diode, which includes from bottom to top: a sapphire substrate, a low-temperature buffer layer GaN, an undoped GaN layer, an N-type GaN layer doped with Si, and a MgInAlN/SiGaN superlattice layer. , In _x Ga _(1-x) N/GaN light-emitting layer, P-type AlGaN layer and P-type GaN layer doped with magnesium; wherein, the MgInAlN/SiGaN superlattice layer is made by the following steps:

In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000°C, and the flow rate is 50000-55000sccm of _NH3 , 50-70sccm of TMGa, 90-110L/min of _H2 , 1200-1400sccm of TMIn, 100- Under the conditions of 200sccm TMAl, 900-1000sccm Cp ₂ Mg, and 20-30sccm SiH ₄ , grow the MgInAlN/SiGaN superlattice layer:

In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000°C, and the flow rate is 50000-55000sccm of _NH3 , 100-200sccm of TMAl, 90-110L/min of _H2 , 1200-1400sccm of TMIn and 900- Under the condition of 1000sccm Cp ₂ Mg, grow a 4-7nm MgInAlN layer, wherein the In doping concentration is 3E19-4E19atom/cm ³ , and the Mg doping concentration is 1E19-1E20atom/cm ³ ;

In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000℃, and the flow rate is 50000-55000sccm _NH3 , 90-110L/min _H2 , 50-70sccm TMGa, 20-30sccm _SiH4 conditions Next, grow a SiGaN layer, wherein the Si doping concentration is 1E18-5E18atom/cm ³ ;

The MgInAlN/SiGaN superlattice layer is obtained by periodically growing the MgInAlN layer and the SiGaN layer, wherein the growth period is 4-20.

Compared with the prior art, the light-emitting diode epitaxial growth method and the light-emitting diode of the present invention have achieved the following beneficial effects:

(1) In the light-emitting diode epitaxial growth method and the light-emitting diode of the present invention, a MgInAlN/SiGaN superlattice layer is grown on the Si-doped N-type GaN layer, and the high-energy band of the SiGaN layer is used as a potential to block electrons to prevent electrons from Propagate from the Si-doped N-type GaN layer to the light-emitting layer too quickly, so that when the crowded electrons propagating vertically meet the SiGaN layer, they are blocked by the high-energy band of the SiGaN layer and properly diffused laterally, so that the current in the LED epitaxial structure is uniform. distribution, thereby avoiding the problem of high resistance caused by uneven current distribution in the LED epitaxial structure, and improving the luminous efficiency of the LED.

(2) In the light-emitting diode epitaxial growth method and the light-emitting diode of the present invention, a MgInAlN/SiGaN superlattice layer is grown on the Si-doped N-type GaN layer, and the MgInAlN/SiGaN superlattice layer can form a high-concentration di Two-dimensional electron gas, using the high lateral mobility of two-dimensional electron gas, accelerates the lateral expansion of electrons in the LED, so that the macroscopic current is effectively expanded when passing through the MgInAlN/SiGaN superlattice layer, making the current distribution of the light-emitting layer Become uniform, the use of MgInAlN/SiGaN superlattice layer can improve the performance of LED in all aspects.

Of course, any product implementing the present invention does not necessarily need to achieve all the above-mentioned technical effects at the same time.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

FIG. 1 is a schematic flow chart of an LED structure epitaxial growth method in the prior art;

Fig. 2 is the structural representation of LED prepared by the method in Fig. 1;

FIG. 3 is a schematic flow chart of the epitaxial growth method of light-emitting diodes described in Embodiment 1 of the present invention;

4 is a schematic structural diagram of a photodiode prepared by the epitaxial growth method of a light emitting diode described in Example 1 of the present invention;

FIG. 5 is a schematic flow chart of the epitaxial growth method for light emitting diodes described in Embodiment 2 of the present invention.

detailed description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and in no way taken as limiting the invention, its application or uses.

Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods and devices should be considered part of the description.

In all examples shown and discussed herein, any specific values should be construed as exemplary only, and not as limitations. Therefore, other instances of the exemplary embodiment may have different values.

It should be noted that like numerals and letters denote like items in the following figures, therefore, once an item is defined in one figure, it does not require further discussion in subsequent figures.

Example 1

As shown in FIG. 1 and FIG. 2 , FIG. 1 is a schematic flowchart of a method for epitaxial growth of an LED structure in the prior art; FIG. 2 is a schematic structural schematic diagram of an LED prepared by the method in FIG. 1 . The LED structure epitaxial growth method in the prior art includes the following steps:

Step 101, processing the sapphire substrate:

Under the hydrogen atmosphere at 1000-1100°C, feed 100L/min-130L/min H ₂ , keep the reaction chamber pressure at 100-300mbar (air pressure unit), and process the sapphire substrate for 5-10 minutes.

Step 102, growing a low-temperature buffer layer GaN:

Cool down to 500-600°C, keep the reaction chamber pressure at 300-600mbar, and feed NH ₃ at a flow rate of 10,000-20,000sccm (sccm notes standard milliliters per minute), TMGa at 50-100sccm, and H at 100L/min-130L/min _2. A low-temperature buffer layer GaN with a thickness of 20-40 nm is grown on the sapphire substrate.

Step 103, low temperature buffer layer GaN etching treatment:

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

Step 104, growing an undoped GaN layer:

Raise the temperature to 1000-1200°C, keep the reaction chamber pressure at 300-600mbar, and feed NH ₃ with a flow rate of 30,000-40,000sccm (sccm remark standard ml per minute), TMGa at 200-400sccm and H ₂ at 100-130L/min , continuously growing an undoped GaN layer with a thickness of 2-4 μm.

Step 105, growing a first Si-doped N-type GaN layer:

Keep the pressure and temperature of the reaction chamber constant, and feed NH ₃ with a flow rate of 30000-60000 sccm (sccm notes standard milliliters per minute), TMGa with 200-400 sccm, H ₂ with 100-130 L/min and SiH ₄ with 20-50 sccm, Continue to grow the N-type GaN layer first doped with Si with a thickness of 3-4 μm, wherein the Si doping concentration is 5E18atoms/cm3-1E19atoms/cm ³ (Note 1E19 represents 10 to the 19th power, and so on, atoms/cm ³ The unit of doping concentration is the same below).

Step 106, growing a second Si-doped N-type GaN layer:

Keep the pressure and temperature of the reaction chamber constant, and feed NH ₃ with a flow rate of 30,000-60,000 sccm (sccm notes standard milliliters per minute), TMGa at 200-400 sccm, H ₂ at 100-130 L/min, and SiH ₄ at 2-10 sccm, Continuously growing a second Si-doped N-type GaN layer with a thickness of 200-400 nm, wherein the Si doping concentration is 5E17-1E18 atoms/cm ³ .

Step 107, growing an In _x Ga _(1-x) N/GaN light-emitting layer:

Keep the pressure of the reaction chamber at 300-400mbar, the temperature at 700-750°C, the flow rate of 50000-70000sccm _NH3 , 20-40sccm TMGa, 1500-2000sccm TMIn and 100-130L/min _N2 , the growth thickness An In _x Ga _(1-x) N layer (x=0.20-0.25) doped with In of 2.5-3.5nm, with an emission wavelength of 450-455nm;

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

Then repeat the growth of the In _x Ga _(1-x) N layer, and then repeat the growth of the GaN layer, alternately grow to obtain the In _x Ga _(1-x) N/GaN light emitting layer, and control the number of cycles to 7-15.

Step 108, growing a P-type AlGaN layer:

Keep the pressure of the reaction chamber at 200-400mbar, the temperature at 900-950°C, and the flow rate of NH ₃ at 50000-70000sccm, TMGa at 30-60sccm, _H2 at 100-130L/min, TMAl at 100-130sccm and 1000- 1300 sccm of Cp ₂ Mg, continuously growing a P-type AlGaN layer with a thickness of 50-100 nm, wherein, the Al doping concentration is 1E20-3E20, and the Mg doping concentration is 1E19-1E20.

Step 109, growing a p-type GaN layer doped with magnesium:

Keep the pressure of the reaction chamber at 400-900 mbar, the temperature at 950-1000 ° C, and feed the flow rate of 50000-70000 sccm of NH ₃ , 20-100 sccm of TMGa, 100-130 L/min of H ₂ and 1000-3000 sccm of Cp ₂ Mg, A magnesium-doped P-type GaN layer with a thickness of 50-200 nm is continuously grown, wherein the Mg doping concentration is 1E19-1E20.

Step 110, cooling down, cooling down:

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

The structure of LED in Fig. 2 comprises: substrate sapphire substrate 201, low-temperature buffer layer GaN layer 202, undoped GaN layer 203, N-type GaN layer 204 doped with Si, light-emitting layer 205 (by In _x Ga _{(1- x)} N layer and GaN layer are periodically grown), P-type AlGaN layer 206, Mg-doped P-type GaN layer 207, ITO layer 208, protective layer SiO ₂ layer 209, P electrode 210 and N electrode 211.

When the LED prepared by the existing technology is working, electrons can travel from the N-type GaN layer to the light-emitting layer at a relatively fast speed, causing the electrons traveling in the longitudinal direction to be crowded, resulting in an uneven distribution of current in the light-emitting layer in the LED. Uniformity, which in turn affects the luminous efficiency of the LED. In order to solve the above-mentioned problems in the prior art, this embodiment provides a method for epitaxial growth of light-emitting diodes as follows:

As shown in Fig. 3, it is a schematic flow chart of the epitaxial growth method of light-emitting diodes described in this implementation, and the method includes the following steps:

Step 301, processing the sapphire substrate.

Step 302 , growing a low-temperature buffer layer GaN.

Step 303, low temperature buffer layer GaN etching treatment

Step 304 , growing an undoped GaN layer.

Step 305 , growing a Si-doped N-type GaN layer.

Step 306, growing the MgInAlN/SiGaN superlattice layer: in the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000°C, and the flow rate is 50000-55000sccm of NH ₃ , 50-70sccm of TMGa, 90-110L/min The MgInAlN/SiGaN superlattice layer is grown under the conditions of H ₂ of 1200-1400 sccm, TMAl of 100-200 sccm, Cp ₂ Mg of 900-1000 sccm, and SiH ₄ of 20-30 sccm.

In some optional embodiments, the growth of the MgInAlN/SiGaN superlattice layer may be: NH ₃ , 100-200 sccm at a reaction chamber pressure of 500-750 mbar, temperature of 950-1000 ° C, and flow rate of 50000-55000 sccm Under the conditions of TMAl of 90-110L/min, H ₂ of 90-110L/min, TMIn of 1200-1400sccm and Cp ₂ Mg of 900-1000sccm, a MgInAlN layer of 4-7nm is grown, wherein, the In doping concentration is 3E19-4E19atom/cm ³ , Mg doping concentration is 1E19-1E20atom/cm ³ ;

In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000℃, and the flow rate is 50000-55000sccm _NH3 , 90-110L/min _H2 , 50-70sccm TMGa, 20-30sccm _SiH4 conditions Next, grow a SiGaN layer with a thickness of 8-15nm, wherein the Si doping concentration is 1E18-5E18atom/cm ³ ;

The MgInAlN/SiGaN superlattice layer is obtained by periodically growing the MgInAlN layer and the SiGaN layer, wherein the growth period is 4-20.

The SiGaN layer in the MgInAlN/SiGaN superlattice layer has a high-energy band, and the high-energy band of the SiGaN layer acts as a barrier to prevent electrons from propagating too quickly from the N-type GaN layer to the light-emitting layer, avoiding the crowding of electrons in the light-emitting layer and causing the resistance to increase. The situation makes the current distribution in the light-emitting layer uniform, thereby improving the luminous efficiency of the LED.

Step 307, growing an In _x Ga _(1-x) N/GaN light emitting layer.

Step 308 , growing a P-type AlGaN layer.

Step 309 , growing a p-type GaN layer doped with magnesium.

Step 310, cooling down to obtain light-emitting diodes:

Cool down to 650-680°C and keep warm for 20-30 minutes, then turn off the heating system, turn off the gas supply system and cool down with the furnace to obtain light-emitting diodes.

As shown in Figure 4, it is a schematic structural diagram of a photodiode prepared by the epitaxial growth method of a light emitting diode described in this embodiment. The photodiode includes: a substrate sapphire substrate 401, a low-temperature buffer layer GaN layer 402, an undoped GaN layer 403, Si-doped N-type GaN layer 404, MgInAlN/SiGaN superlattice layer 405, light emitting layer 406 (obtained by periodic growth of In _x Ga _(1-x) N layer and GaN layer), P-type AlGaN layer 407 , Mg-doped P-type GaN layer 408, ITO layer 409, protective layer SiO ₂ layer 410, P electrode 411 and N electrode 412.

Example 2

As shown in FIG. 5, it is a schematic flow chart of the epitaxial growth method of light-emitting diodes described in this embodiment. The method includes the following steps:

Step 501, processing the sapphire substrate: in a hydrogen atmosphere at 1000-1100°C, inject 100L/min-130L/min of _H2 , and keep the reaction chamber pressure at 100-300mbar, and process the sapphire substrate for 5-10 minute.

Step 502, growing low-temperature buffer layer GaN: at a temperature of 500-600°C, a reaction chamber pressure of 300-600mbar, and a flow rate of 10000-20000sccm of NH ₃ , 50-100sccm of TMGa and 100L/min-130L/min Under the condition of H ₂ , grow a low-temperature buffer layer GaN with a thickness of 20-40nm on the sapphire substrate.

Step 503, low-temperature buffer layer GaN etching treatment: raise the temperature to 1000-1100°C, keep the reaction chamber pressure at 300-600mbar, and feed in _NH3 at a flow rate of 30000-40000sccm and _H2 at 100L/min-130L/min Under the conditions, keep the temperature stable for 300-500 seconds to etch the low-temperature buffer layer GaN into an irregular island shape.

Step 504, growing an undoped GaN layer: at a temperature of 1000-1200° C., a reaction chamber pressure of 300-600 mbar, and a flow rate of 30,000-40,000 sccm of NH ₃ , 200-400 sccm of TMGa, and 100-130 L/min of H Under the condition of ₂ , a 2-4μm undoped GaN layer is continuously grown.

Step 505, growing Si-doped N-type GaN layer: In the reaction chamber, the pressure is 300-600mbar, the temperature is 1000-1200°C, and the flow rate is 30000-60000sccm of NH ₃ , 200-400sccm of TMGa, 100-130L/ Under the conditions of min H ₂ and 20-50 sccm SiH ₄ , a Si-doped N-type GaN layer with a thickness of 3-4 μm is continuously grown, wherein the Si doping concentration is 5E18-1E19 atom/cm ³ .

Step 506, growing the MgInAlN/SiGaN superlattice layer: in the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000°C, and the flow rate is 50000-55000sccm of NH ₃ , 50-70sccm of TMGa, 90-110L/min The MgInAlN/SiGaN superlattice layer is grown under the conditions of H ₂ of 1200-1400 sccm, TMAl of 100-200 sccm, Cp ₂ Mg of 900-1000 sccm, and SiH ₄ of 20-30 sccm.

In some optional embodiments, the growth of the MgInAlN/SiGaN superlattice layer may be: NH ₃ , 100-200 sccm at a reaction chamber pressure of 500-750 mbar, temperature of 950-1000 ° C, and flow rate of 50000-55000 sccm Under the conditions of TMAl of 90-110L/min, H ₂ of 90-110L/min, TMIn of 1200-1400sccm and Cp ₂ Mg of 900-1000sccm, a MgInAlN layer of 4-7nm is grown, wherein, the In doping concentration is 3E19-4E19atom/cm ³ , Mg doping concentration is 1E19-1E20atom/cm ³ ;

In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000℃, and the flow rate is 50000-55000sccm _NH3 , 90-110L/min _H2 , 50-70sccm TMGa, 20-30sccm _SiH4 conditions Next, grow a SiGaN layer, wherein the Si doping concentration is 1E18-5E18atom/cm ³ ;

The MgInAlN/SiGaN superlattice layer is obtained by periodically growing the MgInAlN layer and the SiGaN layer, wherein the growth period is 4-20. This embodiment does not limit the growth sequence of the MgInAlN layer and the SiGaN layer. It is also possible to grow the SiGaN layer first, then grow the MgInAlN layer, and then alternately grow the SiGaN layer and the MgInAlN layer periodically to obtain the MgInAlN/SiGaN superlattice layer.

The SiGaN layer in the MgInAlN/SiGaN superlattice layer has a high-energy band, and the high-energy band of the SiGaN layer acts as a barrier to prevent electrons from propagating too quickly from the N-type GaN layer to the light-emitting layer, avoiding the crowding of electrons in the light-emitting layer and causing the resistance to increase. The situation makes the current distribution in the light-emitting layer uniform, thereby improving the luminous efficiency of the LED.

Step 507, growing an In _x Ga _(1-x) N layer: In the reaction chamber, the pressure is 300-400 mbar, the temperature is 700-750 ° C, and the flow rate is 50000-70000 sccm NH ₃ , 20-40 sccm TMGa, 1500- Under the conditions of 2000sccm TMIn and 100-130L/min N ₂ , grow an In-doped In _x Ga _(1-x) N layer (x=0.20-0.25) with a thickness of 2.5-3.5nm, and the emission wavelength is 450- 455nm.

Step 508, growing the GaN layer: raise the temperature to 750-850°C, the pressure in the reaction chamber is 300-400mbar, and the flow rate is 50000-70000sccm of NH ₃ , 20-100sccm of TMGa and 100-130L/min of _N2 Under the conditions of , grow a GaN layer with a thickness of 8-15nm;

Step 509, growing an In _x Ga _(1-x) N/GaN light-emitting layer: periodically and alternately growing the In _x Ga _(1-x) N layer and the GaN layer to obtain In _x Ga _(1-x) N/GaN light emission layer, wherein the number of growth cycles is 7-15. This embodiment does not limit the sequential growth sequence of the In _x Ga _(1-x) N layer and the GaN layer, it is also possible to grow the GaN layer first, then grow the In _x Ga _(1-x) N layer, and then grow GaN alternately periodically layer and an In _x Ga _(1-x) N layer to obtain an In _x Ga _(1-x) N/GaN light emitting layer.

Step 510, growing a P-type AlGaN layer: In the reaction chamber, the pressure is 200-400mbar, the temperature is 900-950°C, and the flow rate is 50000-70000sccm of NH ₃ , 30-60sccm of TMGa, and 100-130L/min of _H2 , TMAl of 100-130sccm and Cp ₂ Mg of 1000-1300sccm, continuously grow a P-type AlGaN layer with a thickness of 50-100nm, wherein, the Al doping concentration is 1E20-3E20atom/cm ³ , and the Mg doping concentration is 1E19 -1E20atom/cm ³ .

Step 511, growing a P-type GaN layer doped with magnesium: in the reaction chamber, the pressure is 400-900mbar, the temperature is 950-1000°C, and the flow rate is 50000-70000sccm of NH ₃ , 20-100sccm of TMGa, 100-130L/min Under the conditions of H ₂ and 1000-3000sccm Cp ₂ Mg, a magnesium-doped P-type GaN layer with a thickness of 50-200nm is continuously grown, wherein the Mg doping concentration is 1E19-1E20atom/cm ³ .

Step 512 , cooling down to obtain light-emitting diodes: cooling down to 650-680° C. and keeping warm for 20-30 minutes, then turning off the heating system and gas supply system to cool down in the furnace to obtain light-emitting diodes.

Example 3

This example provides a comparison example of the luminous performance of the light-emitting diode of the present invention and the light-emitting diode of the traditional solution. The comparative method of the present embodiment comprises the following contents:

Sample 1 is prepared according to the traditional LED growth method, and sample 2 is prepared according to the method described in the present invention; the difference between sample 1 and sample 2 epitaxial growth method parameters is: the preparation process of sample 2 grows a MgInAlN/SiGaN superlattice layer, sample The growth conditions of other epitaxial layers of sample 1 and sample 2 are exactly the same (please refer to Table 1). Sample 1 and sample 2 were plated with an ITO layer with a thickness of about 150nm under the same pre-process conditions, and a Cr/Pt/Au electrode with a thickness of about 1500nm was plated under the same conditions, and the plated thickness was about 1500nm under the same conditions. 100nm SiO ₂ protective layer, and then grind and cut the sample into chip particles of 635μm*635μm (25mil*25mil) under the same conditions, and then select 100 crystal grains in the same position for sample 1 and sample 2, in the same package Under the advanced technology, it is packaged into a white light LED. 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.

The following is the comparison table of the growth parameters of the light-emitting layer of sample 1 and sample 2 and the comparison table of the electrical test parameters of sample 1 and sample 2.

Table 1. Comparison table of growth parameters of luminescent layer

Table 2. Comparison table of electrical test parameters of samples 1 and 2

It can be seen from Table 1 and Table 2 that: after analyzing and comparing the data of sample 1 and sample 2 product electrical test parameters, the LEDs prepared by the LED growth method provided by the present invention have higher luminous efficiency, and the electrical properties of other LEDs are higher. The parameters also become better, and the experimental data proves that the method of the present invention can improve the feasibility of the light efficiency of LED products.

It can be known from the above embodiments that the light-emitting diode epitaxial growth method and the light-emitting diode of the present invention have achieved the following beneficial effects:

(1) In the light-emitting diode epitaxial growth method and the light-emitting diode of the present invention, a MgInAlN/SiGaN superlattice layer is grown on the Si-doped N-type GaN layer, and the high-energy band of the SiGaN layer is used as a potential to block electrons to prevent electrons from Propagate from the Si-doped N-type GaN layer to the light-emitting layer too quickly, so that when the crowded electrons propagating vertically meet the SiGaN layer, they are blocked by the high-energy band of the SiGaN layer and properly diffused laterally, so that the current in the LED epitaxial structure is uniform. distribution, thereby avoiding the problem of high resistance caused by uneven current distribution in the LED epitaxial structure, and improving the luminous efficiency of the LED.

(2) In the light-emitting diode epitaxial growth method and the light-emitting diode of the present invention, a MgInAlN/SiGaN superlattice layer is grown on the Si-doped N-type GaN layer, and the MgInAlN/SiGaN superlattice layer can form a high-concentration di Two-dimensional electron gas, using the high lateral mobility of two-dimensional electron gas, accelerates the lateral expansion of electrons in the LED, so that the macroscopic current is effectively expanded when passing through the MgInAlN/SiGaN superlattice layer, making the current distribution of the light-emitting layer Become uniform, the use of MgInAlN/SiGaN superlattice layer can improve the performance of LED in all aspects.

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods, apparatuses, or computer program products. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention 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.

Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and not intended to limit the scope of the present invention. Those skilled in the art will appreciate that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims (10)

1. A light-emitting diode epitaxial growth method, characterized in that, comprising: processing a sapphire substrate, growing a low-temperature buffer layer GaN, growing an undoped GaN layer, growing an N-type GaN layer doped with Si, growing a MgInAlN/SiGaN supercrystal grid layer, growing In _x Ga _(1-x) N/GaN light-emitting layer, growing P-type AlGaN layer, growing magnesium-doped P-type GaN layer, and cooling to obtain a light-emitting diode; wherein, growing the MgInAlN/SiGaN superlattice layer, further comprising: In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000°C, and the flow rate is 50000-55000sccm of _NH3 , 50-70sccm of TMGa, 90-110L/min of _H2 , 1200-1400sccm of TMIn, 100- Under the conditions of 200sccm TMAl, 900-1000sccm Cp ₂ Mg, and 20-30sccm SiH ₄ , grow the MgInAlN/SiGaN superlattice layer: In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000°C, and the flow rate is 50000-55000sccm of _NH3 , 100-200sccm of TMAl, 90-110L/min of _H2 , 1200-1400sccm of TMIn and 900- Under the condition of 1000sccm Cp ₂ Mg, grow a 4-7nm MgInAlN layer, wherein the In doping concentration is 3E19-4E19atom/cm ³ , and the Mg doping concentration is 1E19-1E20atom/cm ³ ; In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000℃, and the flow rate is 50000-55000sccm _NH3 , 90-110L/min _H2 , 50-70sccm TMGa, 20-30sccm _SiH4 conditions Next, grow a SiGaN layer with a thickness of 8-15nm, wherein the Si doping concentration is 1E18-5E18atom/cm ³ ; Periodically grow MgInAlN layers and SiGaN layers to obtain MgInAlN/SiGaN superlattice layers, wherein the growth period is 4-20; The light-emitting diode obtained by cooling down further includes: Cool down to 650-680°C and keep warm for 20-30 minutes, then turn off the heating system, turn off the gas supply system and cool down with the furnace to obtain light-emitting diodes. 2. The light-emitting diode epitaxial growth method according to claim 1, characterized in that, processing the sapphire substrate is further: In a hydrogen atmosphere at 1000-1100°C, 100L/min-130L/min of H ₂ is introduced, and the reaction chamber pressure is kept at 100-300mbar, and the sapphire substrate is processed for 5-10 minutes. 3. The light-emitting diode epitaxial growth method according to claim 1, characterized in that, growing the low-temperature buffer layer GaN is further: Under the conditions of a temperature of 500-600°C, a reaction chamber pressure of 300-600mbar, a flow rate of 10000-20000sccm of NH ₃ , 50-100sccm of TMGa and 100L/min-130L/min of _H2 , the sapphire substrate A low-temperature buffer layer GaN with a thickness of 20-40nm is grown on the bottom. 4. The light-emitting diode epitaxial growth method according to claim 3, further comprising: Raise the temperature to 1000-1100°C, keep the pressure of the reaction chamber at 300-600mbar, feed the flow rate of 30000-40000sccm of _NH3 and 100L/min-130L/min of _H2 , and keep the temperature stable for 300-500 seconds to etch the low-temperature buffer layer GaN into irregular island shapes. 5. The light-emitting diode epitaxial growth method according to claim 1, characterized in that, growing an undoped GaN layer is further: Under the conditions of a temperature of 1000-1200°C, a reaction chamber pressure of 300-600mbar, a flow rate of 30000-40000sccm of NH ₃ , 200-400sccm of TMGa and 100-130L/min of _H2 , the continuous growth thickness is 2 -4 μm undoped GaN layer. 6. The light-emitting diode epitaxial growth method according to claim 1, characterized in that, growing an N-type GaN layer doped with Si is further: In the reaction chamber, the pressure is 300-600mbar, the temperature is 1000-1200℃, the flow rate is 30000-60000sccm _NH3 , 200-400sccm TMGa, 100-130L/min _H2 and 20-50sccm _SiH4 conditions Next, continuously grow a Si-doped N-type GaN layer with a thickness of 3-4 μm, wherein the Si doping concentration is 5E18-1E19 atom/cm ³ . 7. The light-emitting diode epitaxial growth method according to claim 1, characterized in that, growing an InxGa _{(1-x) N} /GaN light-emitting layer is further: Under the condition of reaction chamber pressure of 300-400mbar, temperature of 700-750℃, flow rate of 50000-70000sccm of _NH3 , 20-40sccm of TMGa, 1500-2000sccm of TMIn and 100-130L/min of _N2 , growing an In-doped In _x Ga _(1-x) N layer (x=0.20-0.25) with a thickness of 2.5-3.5nm, and an emission wavelength of 450-455nm; Raise the temperature to 750-850°C, under the condition that the reaction chamber pressure is 300-400mbar, the flow rate is 50000-70000sccm of _NH3 , 20-100sccm of TMGa and 100-130L/min of _N2 , the growth thickness is 8-15nm GaN layer; The In _x Ga _(1-x) N/GaN light-emitting layer is obtained by periodically growing the In _x Ga _(1-x) N layer and the GaN layer alternately, wherein the number of growth cycles is 7-15. 8. The light-emitting diode epitaxial growth method according to claim 1, characterized in that growing a P-type AlGaN layer further comprises: In the reaction chamber, the pressure is 200-400mbar, the temperature is 900-950°C, and the flow rate is 50000-70000sccm of _NH3 , 30-60sccm of TMGa, 100-130L/min of _H2 , 100-130sccm of TMAl and 1000- Under the condition of 1300sccm Cp ₂ Mg, a P-type AlGaN layer with a thickness of 50-100nm is continuously grown, wherein the Al doping concentration is 1E20-3E20atom/cm ³ , and the Mg doping concentration is 1E19-1E20atom/cm ³ . 9. The light-emitting diode epitaxial growth method according to claim 1, characterized in that, growing a p-type GaN layer doped with magnesium is further: In the reaction chamber, the pressure is 400-900mbar, the temperature is 950-1000℃, and the flow rate is 50000-70000sccm of _NH3 , 20-100sccm of TMGa, _100-130L /min of _H2 and 1000-3000sccm of Cp2Mg. Under the conditions, a magnesium-doped P-type GaN layer with a thickness of 50-200 nm is continuously grown, wherein the Mg doping concentration is 1E19-1E20 atom/cm ³ . 10. A light-emitting diode, characterized in that it comprises, from bottom to top: a sapphire substrate, a low-temperature buffer layer GaN, an undoped GaN layer, an N-type GaN layer doped with Si, a MgInAlN/SiGaN superlattice layer, an In _x Ga _(1-x) N/GaN light-emitting layer, P-type AlGaN layer and P-type GaN layer doped with magnesium; wherein, the MgInAlN/SiGaN superlattice layer is made by the following steps: In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000°C, and the flow rate is 50000-55000sccm of _NH3 , 50-70sccm of TMGa, 90-110L/min of _H2 , 1200-1400sccm of TMIn, 100- Under the conditions of 200sccm TMAl, 900-1000sccm Cp ₂ Mg, and 20-30sccm SiH ₄ , grow the MgInAlN/SiGaN superlattice layer: In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000°C, and the flow rate is 50000-55000sccm of _NH3 , 100-200sccm of TMAl, 90-110L/min of _H2 , 1200-1400sccm of TMIn and 900- Under the condition of 1000sccm Cp ₂ Mg, grow a 4-7nm MgInAlN layer, wherein the In doping concentration is 3E19-4E19atom/cm ³ , and the Mg doping concentration is 1E19-1E20atom/cm ³ ; In the reaction chamber, the pressure is 500-750mbar, the temperature is 950-1000℃, and the flow rate is 50000-55000sccm _NH3 , 90-110L/min _H2 , 50-70sccm TMGa, 20-30sccm _SiH4 conditions Next, grow a SiGaN layer, wherein the Si doping concentration is 1E18-5E18atom/cm ³ ; The MgInAlN/SiGaN superlattice layer is obtained by periodically growing the MgInAlN layer and the SiGaN layer, wherein the growth period is 4-20.