CN117410409A - Light-emitting diode - Google Patents

Abstract

The invention relates to the technical field of semiconductors, in particular to a light-emitting diode. The light-emitting diode comprises a substrate, a buffer layer, an N-type semiconductor layer, a stress release layer, a multi-quantum well light-emitting layer and a P-type semiconductor layer; the stress release layer comprises a first sub-layer and a second sub-layer which are arranged on the N-type semiconductor layer in a stacking way at least one period; the first sub-layer comprises at least two of a GaN layer doped with a first impurity, an undoped GaN layer and an InGaN layer; the second sub-layer is an AlGaN layer. According to the invention, the AlGaN layer is arranged, so that the forbidden bandwidth of the stress release layer can be increased, the potential barrier is increased, and the probability of holes penetrating from the bottom of the V-shaped pit to the stress release layer under high current density is greatly reduced; the existence of the high potential barrier enables the current distribution to be more uniform when electrons enter the multi-quantum well luminous layer; and the higher potential barrier also increases the effect of dislocation shielding, reduces the non-radiative recombination probability and improves the light efficiency.

Description

a light emitting diode

The application for this invention is a divisional application with a filing date of February 17, 2022, an application number of 2022101466319, and an invention title of “A Light-Emitting Diode”.

Technical field

The present invention relates to the field of semiconductor technology, and specifically to a light-emitting diode.

Background technique

Light Emitting Diode (LED) can efficiently convert electrical energy into light energy. It is a light-emitting device that releases energy to emit light through the recombination of electrons and holes. It is widely used in lighting, displays and other fields.

As the core part of LED, epitaxial wafer has received more and more attention and research in recent years. The structures of currently commonly used epitaxial wafers include: substrate, N-type GaN semiconductor layer, stress relief layer, multi-quantum well multi-quantum well light-emitting layer and P-type GaN semiconductor layer.

Among them, when GaN is grown at low temperature, the lateral migration ability of Ga atoms is weak, which easily causes threading dislocations to form V-type defects. The V-shaped pits serve as hole transmission channels, which are beneficial to improving the hole and electron recombination efficiency.

However, with the help of V-shaped pit hole transport, under high current density, holes will penetrate from the bottom of the V-shaped pit to the stress release layer and recombine with electrons in the stress release layer. The bandgap width in the stress release layer is different from the bandgap width of the multi-quantum well light-emitting layer, which results in the emission wavelength here being inconsistent with the multi-quantum well. This will lead to poor luminescence concentration of the device, and the half-width of the luminescence spectrum will become larger. Effectiveness decreases.

In view of this, the present invention is proposed.

Contents of the invention

The first object of the present invention is to provide a light-emitting diode. By arranging an AlGaN layer in the stress release layer, the bandgap width of the stress release layer can be increased, the potential barrier can be increased, and the holes can be greatly reduced from V under high current density. The probability of the bottom of the pit penetrating into the stress release layer; the existence of a high potential barrier makes the current distribution more uniform when electrons enter the multi-quantum well light-emitting layer; at the same time, a higher potential barrier also increases the dislocation shielding effect and reduces Non-radiative recombination probability to improve light efficiency.

In order to achieve the above objects of the present invention, the following technical solutions are adopted:

The invention provides a light-emitting diode, which includes a substrate, a buffer layer, an N-type semiconductor layer, a stress release layer, a multi-quantum well light-emitting layer and a P-type semiconductor layer that are sequentially stacked on the surface of the substrate;

Wherein, the stress relief layer includes a first sub-layer and a second sub-layer arranged in at least one periodic stack on the N-type semiconductor layer;

The first sub-layer includes at least two of a GaN layer doped with a first impurity, an undoped GaN layer and an InGaN layer;

The second sub-layer is an AlGaN layer.

Preferably, the stress relief layer includes a first sub-layer and a second sub-layer stacked on the N-type semiconductor layer for 2 to 5 periods.

Preferably, the stress relief layer includes a first impurity-doped GaN layer, an undoped GaN layer, an InGaN layer and an AlGaN layer that are sequentially stacked on the N-type semiconductor layer and grown periodically alternately;

Alternatively, the stress relief layer includes a first impurity-doped GaN layer, an InGaN layer and an AlGaN layer that are sequentially stacked on the N-type semiconductor layer and grow periodically alternately;

Alternatively, the stress relief layer includes an undoped GaN layer, an InGaN layer and an AlGaN layer that are sequentially stacked on the N-type semiconductor layer and grow periodically alternately;

Alternatively, the stress relief layer includes a first impurity-doped GaN layer, an undoped GaN layer and an AlGaN layer that are sequentially stacked on the N-type semiconductor layer and grow periodically alternately.

Preferably, the thickness of the GaN layer doped with the first impurity is

And/or, the thickness of the undoped GaN layer is

And/or, the thickness of the InGaN layer is

And/or, the thickness of the AlGaN layer is

Preferably, the first impurity in the first impurity-doped GaN layer includes carbon and/or silicon;

Preferably, the carbon doping concentration is 1×10 ¹⁷ to 5×10 ¹⁷ atoms/cm ³ ;

Preferably, the doping concentration of silicon is 1×10 ¹⁸ to 5×10 ¹⁸ atoms/cm ³ .

Preferably, the first sub-layer has a periodic structure, and the first sub-layer includes 2 to 5 cycles of alternately stacked GaN layers doped with the first impurity and undoped GaN layers;

Alternatively, the first sub-layer includes alternately stacked GaN layers and InGaN layers doped with the first impurity;

Alternatively, the first sub-layer includes undoped GaN layers and InGaN layers that are alternately stacked;

Alternatively, the first sub-layer includes an alternately stacked GaN layer doped with the first impurity, an undoped GaN layer and an InGaN layer.

Preferably, the stress relief layer includes a first sub-layer and a second sub-layer, wherein the first sub-layer has a periodic structure, the second sub-layer has a single-layer structure, and the second sub-layer is provided between the first sub-layer and the multi-quantum well light-emitting layer.

Preferably, the AlGaN layer is also doped with silicon;

Preferably, the doping concentration of silicon is 1×10 ¹⁸ to 5×10 ¹⁸ atoms/cm ³ .

Preferably, the N-type semiconductor layer includes an undoped GaN layer and/or an N-type GaN layer doped with a second impurity;

Preferably, the second impurity includes Si;

Preferably, the doping concentration of the second impurity is 1×10 ¹⁹ to 5×10 ¹⁹ atoms/cm ³ .

Preferably, the P-type semiconductor layer includes a P-type GaN layer doped with a third impurity;

Preferably, the third impurity includes Mg;

Preferably, the doping concentration of the third impurity is 1×10 ¹⁹ to 1×10 ²¹ atoms/cm ³ .

Compared with the prior art, the beneficial effects of the present invention are:

(1) The light-emitting diode provided by the present invention, by arranging an AlGaN layer in the stress release layer, increases the bandgap width at the stress release layer, improves the potential barrier, and greatly reduces the hole flow from V under high current density. The probability that the bottom of the pit penetrates into the stress release layer reduces the half-width of the luminescence spectrum. The existence of a high potential barrier makes the current distribution more uniform when electrons enter the multi-quantum well light-emitting layer; at the same time, a higher potential barrier also increases the dislocation shielding effect, reduces the probability of non-radiative recombination, and improves the luminous efficiency.

(2) In the light-emitting diode provided by the present invention, by providing an InGaN layer, In in this layer serves as the starting point of V-pits (V-shaped pits), which is beneficial to the generation of V-pits and increases the density of V-pits.

(3) The light-emitting diode provided by the present invention can fully release the underlying stress by arranging the GaN layer doped with the first impurity, provide a low-stress growth foundation for the growth of the AlGaN layer, and improve the crystal growth quality of the AlGaN layer.

Description of the drawings

In order to more clearly explain the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings that need to be used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description The drawings illustrate some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting any creative effort.

Figure 1 is a schematic structural diagram of a light-emitting diode provided by the present invention;

Figure 2 is a schematic structural diagram of a V-shaped defect generated by the light-emitting diode provided by the present invention;

Figure 3 is a schematic structural diagram of another light-emitting diode provided by the present invention that generates V-shaped defects;

Figure 4 is a schematic structural diagram of a light-emitting diode provided in Embodiment 1 of the present invention;

Figure 5 is a schematic structural diagram of the stress release layer of the light-emitting diode provided in Embodiment 1 of the present invention;

Figure 6 is a schematic structural diagram of the stress release layer of the light-emitting diode provided in Embodiment 2 of the present invention;

Figure 7 is a schematic structural diagram of the stress release layer of the light-emitting diode provided in Embodiment 3 of the present invention;

Figure 8 is a schematic structural diagram of the stress release layer of the light-emitting diode provided in Embodiment 4 of the present invention;

Figure 9 is a partial structural schematic diagram of a light-emitting diode provided in Embodiment 5 of the present invention;

Figure 10 is a partial structural diagram of a light-emitting diode provided in Embodiment 6 of the present invention;

Figure 11 is a partial structural diagram of a light-emitting diode provided in Embodiment 7 of the present invention;

FIG. 12 is a partial structural diagram of a light-emitting diode provided in Embodiment 8 of the present invention.

Reference signs:

10-Substrate; 20-Buffer layer; 30-N-type semiconductor layer;

301-Non-doped GaN layer; 302-Si-doped N-type GaN layer; 40-Stress release layer;

401-GaN layer doped with the first impurity; 402-Undoped GaN layer; 403-InGaN layer;

404-AlGaN layer; 50-multiple quantum well light-emitting layer; 60-P-type semiconductor layer;

601-P-type AlGaN electron blocking layer; 602-Mg-doped P-type GaN layer.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific implementation modes. However, those skilled in the art will understand that the following described embodiments are some of the embodiments of the present invention, rather than all of them. They are only used to illustrate the invention and should not be construed as limiting the scope of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.

The present invention provides a light-emitting diode. As shown in Figure 1, the light-emitting diode includes a substrate 10, and a buffer layer 20, an N-type semiconductor layer 30, and a stress relief layer 40 that are sequentially stacked on the surface of the substrate 10. , multi-quantum well light-emitting layer 50 and P-type semiconductor layer 60;

Wherein, the stress relief layer 40 includes a first sub-layer and a second sub-layer arranged in at least one periodic stack on the N-type semiconductor layer 30;

The first sub-layer includes at least two of a GaN layer doped with a first impurity, an undoped GaN layer and an InGaN layer;

The second sub-layer is an AlGaN layer.

When GaN is grown at low temperature, the lateral migration ability of Ga atoms is weak, which easily causes threading dislocations to form V-type defects. The V-type defect provides a hole transmission channel, and the holes generated in the P-type layer can be transported to the multi-quantum well light-emitting layer through the V-type defect, as shown in C1 in Figure 2. However, under high current density, holes have a certain probability of being transmitted to the stress release layer through V-shaped defects and recombination with electrons in the stress release layer, as shown in C2 in Figure 2; while holes transmitted to the stress release layer The luminescence wavelength produced by the recombination of holes and electrons is inconsistent with the luminescence wavelength produced in the multi-quantum well luminescent layer, which will cause the device's luminescence concentration to become worse, the half-width of the luminescence spectrum to become larger, and the light efficiency to decrease.

In order to solve the above problems, the present invention increases the bandgap width at the stress release layer 40 by arranging a second sub-layer, that is, the AlGaN layer, in the stress release layer 40, improves the potential barrier, and greatly reduces the energy consumption under high current density. The probability of holes penetrating from the bottom of the V-shaped pit to the stress release layer 40 reduces the half-width of the luminescence spectrum. As shown in Figure 3, the existence of a high potential barrier makes the current distribution more uniform when electrons enter the multi-quantum well luminescent layer; at the same time , a higher potential barrier also increases the effect of dislocation shielding, reduces the probability of non-radiative recombination, and improves luminous efficiency.

It can be seen that this application solves the technical problem of low light efficiency under high current density existing in the prior art.

In addition, In in the InGaN layer serves as the starting point of V-pits (V-shaped pits), which is beneficial to the generation of V-pits and increases the density of V-pits.

The GaN layer doped with the first impurity can fully release the underlying stress, provide a low-stress growth foundation for the growth of the second sub-layer, and improve the crystal growth quality of the AlGaN layer.

In some specific embodiments of the present invention, the stress relief layer 40 includes a first sub-layer stacked on the N-type semiconductor layer 30 for 2 to 5 cycles (3 cycles or 4 cycles can also be selected). and the second sub-layer.

In some specific embodiments of the present invention, the stress relief layer 40 includes GaN layers 401 doped with first impurities and undoped GaN layers that are sequentially stacked on the N-type semiconductor layer 30 to grow periodically and alternately. layer 402, InGaN layer 403 and AlGaN layer 404.

Among them, by pre-growing the GaN layer 401 doped with the first impurity, the underlying stress can be fully released, providing a low-stress growth foundation for the subsequent growth of the second sub-layer (i.e., the AlGaN layer 404), and improving the length of the AlGaN layer 404. crystal quality.

In in the InGaN layer 403 serves as the starting point of V-pits, which is beneficial to the generation of V-pits and increases the density of V-pits (V-shaped pits).

The undoped GaN layer 402 serves as a transition layer between the first impurity-doped GaN layer 401 and the InGaN layer 403, which can prevent defects from penetrating and extending to the InGaN layer 403, thereby improving the growth quality of the InGaN layer 403.

Alternatively, the stress relief layer 40 includes a first impurity-doped GaN layer 401 , an InGaN layer 403 and an AlGaN layer 404 that are sequentially stacked on the N-type semiconductor layer 30 and grow periodically alternately.

Alternatively, the stress relief layer 40 includes an undoped GaN layer 402 , an InGaN layer 403 and an AlGaN layer 404 that are sequentially stacked on the N-type semiconductor layer 30 and grow periodically alternately.

Alternatively, the stress relief layer 40 includes a GaN layer 401 doped with a first impurity, an undoped GaN layer 402 and an AlGaN layer 404 that are sequentially stacked on the N-type semiconductor layer 30 and grow periodically alternately.

In some specific embodiments of the present invention, the thickness of the GaN layer 401 doped with the first impurity is Including but not limited to/> A pip value of either or a range of values between any two.

And/or, the thickness of the undoped GaN layer 402 is including but not limited to

A pip value of either or a range of values between any two.

And/or, the thickness of the InGaN layer 403 is Including but not limited to/> A pip value of either or a range of values between any two.

And/or, the thickness of the AlGaN layer 404 is Including but not limited to/> A pip value of either or a range of values between any two.

In some specific embodiments of the present invention, the first impurity in the first impurity-doped GaN layer 401 includes carbon and/or silicon.

Preferably, the first impurity is selected from carbon, or the first impurity is selected from a mixture of carbon and silicon. Among them, the role of the carbon element is: doping C in the GaN layer will reduce the growth quality of the layer, which is beneficial to the release of underlying stress. At the same time, C doping will not affect the energy band structure.

Preferably, the doping concentration of the carbon is 1×10 ¹⁷ to 5×10 ¹⁷ atoms/cm ³ ; including but not limited to 2×10 ¹⁷ atoms/cm ³ , 3×10 ¹⁷ atoms/cm ³ , and 4×10 ¹⁷ atoms/cm A point value of any one of ³ or any range value in between.

Preferably, the doping concentration of the silicon is 1×10 ¹⁸ to 5×10 ¹⁸ atoms/cm ³ , including but not limited to 2×10 ¹⁸ atoms/cm ³ , 3×10 ¹⁸ atoms/cm ³ , and 4×10 ¹⁸ atoms/cm A point value of any one of ³ or any range value in between.

In some specific embodiments of the present invention, an ion implantation method is used to grow the GaN layer 401 doped with the first impurity.

Among them, ion implantation technology refers to passing the gas or vapor of the injected element into an ionization chamber to ionize it to form positive ions, and then lead the positive ions from the ionization chamber into a high-voltage electric field to accelerate, so that they can reach a very high speed and be driven into the semiconductor. physical process. Ion implantation has the following advantages: it can ensure extremely high purity of doped ions, the concentration and depth distribution of implanted ions can be precisely controlled, uniform implantation can be achieved over a large area, the substrate temperature can be freely selected during ion implantation, and the ion implantation doping depth can be freely selected. Small.

Preferably, the first sub-layer has a periodic structure, and the first sub-layer includes 2 to 5 cycles of alternately stacked GaN layers doped with the first impurity and undoped GaN layers;

Alternatively, the first sub-layer includes alternately stacked GaN layers and InGaN layers doped with the first impurity;

Alternatively, the first sub-layer includes undoped GaN layers and InGaN layers that are alternately stacked;

Alternatively, the first sub-layer includes an alternately stacked GaN layer doped with the first impurity, an undoped GaN layer and an InGaN layer.

Preferably, the stress relief layer includes a first sub-layer and a second sub-layer, wherein the first sub-layer has a periodic structure, the second sub-layer has a single-layer structure, and the second sub-layer is provided between the first sub-layer and the multi-quantum well light-emitting layer.

In some specific embodiments of the present invention, the AlGaN layer is also doped with silicon;

Preferably, the doping concentration of the silicon is 1×10 ¹⁸ to 5×10 ¹⁸ atoms/cm ³ , including but not limited to 2×10 ¹⁸ atoms/cm ³ , 3×10 ¹⁸ atoms/cm ³ , and 4×10 ¹⁸ atoms/cm A point value of any one of ³ or any range value in between.

In some specific embodiments of the present invention, the N-type semiconductor layer 30 includes an undoped GaN layer and/or an N-type GaN layer doped with a second impurity.

Preferably, the second impurity includes Si.

Preferably, the doping concentration of the second impurity is 1×10 ¹⁹ to 5×10 ¹⁹ atoms/cm ³ , including but not limited to 2×10 ¹⁹ atoms/cm ³ , 3×10 ¹⁹ atoms/cm ³ , 4 The point value of any one of ×10 ¹⁹ atoms/cm ³ or the range value between any two.

In some specific embodiments of the present invention, the thickness of the non-doped GaN layer is 1 to 5 μm (2 μm, 3 μm or 4 μm can also be selected).

And/or, the thickness of the N-type GaN layer doped with the second impurity is 1 to 5 μm (2 μm, 3 μm or 4 μm can also be selected).

In some specific embodiments of the present invention, the P-type semiconductor layer 60 includes a P-type GaN layer doped with a third impurity.

Preferably, the third impurity includes Mg.

Preferably, the doping concentration of the third impurity is 1×10 ¹⁹ to 1×10 ²¹ atoms/cm ³ , including but not limited to 2×10 ¹⁹ atoms/cm ³ , 5×10 ¹⁹ atoms/cm ³ , 8 Any one of ×10 ¹⁹ atoms/cm ³ , 1×10 ²⁰ atoms/cm ³ , 5×10 ²⁰ atoms/cm ³ , 8×10 ²⁰ atoms/cm ³ , and 1×10 ²¹ atoms/cm ³ value or any range of values in between.

Preferably, the thickness of the P-type GaN layer doped with the third impurity is including but not limited to A pip value of either or a range of values between any two.

In some specific embodiments of the present invention, the N-type semiconductor layer 30 further includes a three-dimensional nucleation layer, and the three-dimensional nucleation layer is disposed between the buffer layer 20 and the non-doped GaN layer.

Preferably, the thickness of the three-dimensional nucleation layer is 0.5-2 μm, including but not limited to any point value or any point value of 0.7 μm, 0.9 μm, 1.0 μm, 1.2 μm, 1.5 μm, 1.7 μm, and 1.9 μm. The range of values between the two.

Preferably, the material of the three-dimensional nucleation layer is AlGaN.

In some specific embodiments of the present invention, the material of the buffer layer 20 is AlGaN.

Preferably, the thickness of the buffer layer 20 is Including but not limited to/> A pip value of either or a range of values between any two.

In some specific embodiments of the present invention, the P-type semiconductor layer 60 further includes an electron blocking layer, which is disposed between the multi-quantum well light-emitting layer 50 and the P-type GaN doped with a third impurity. between layers.

In some specific embodiments of the present invention, the electron blocking layer and the P-type GaN layer doped with the third impurity are collectively referred to as a P-type semiconductor layer.

Preferably, the electron blocking layer is made of AlGaN.

Preferably, the thickness of the electron blocking layer is Including but not limited to/> A pip value of either or a range of values between any two.

In some specific embodiments of the present invention, the substrate 10 is a growth substrate, and its material can be any conventional material, or can be set according to specific needs. Preferably, the substrate 10 includes at least one of a sapphire transparent substrate, a composite patterned substrate (such as a sapphire + SiO ₂ composite substrate), a GaN substrate and a SiC substrate.

In some specific embodiments of the present invention, the lattice constant of the buffer layer 20 is between the N-type semiconductor layer 30 and the substrate 10 , which can improve epitaxial quality and reduce lattice defects. Preferably, the buffer layer 20 includes at least one of an AlN buffer layer, a GaN buffer layer, an AlGaN buffer layer and an AlInGaN buffer layer.

In some specific embodiments of the present invention, the method for preparing a light-emitting diode includes the following steps:

The buffer layer 20, the N-type semiconductor layer 30, the stress relief layer 40, the multi-quantum well light-emitting layer 50 and the P-type semiconductor layer 60 are sequentially grown on the surface of the substrate to obtain the light-emitting diode.

In some specific embodiments of the present invention, the growth temperature of the stress relief layer 40 is 850-900°C, including but not limited to any one of 860°C, 870°C, 880°C, 890°C or any point value. The range of values between the two.

And/or, the growth pressure of the stress relief layer 40 is 200-300 mbar, including but not limited to any one point value of 210 mbar, 230 mbar, 250 mbar, 270 mbar, 290 mbar or any range value between the two.

The embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.

Example 1

The structural schematic diagram of the light-emitting diode provided in this embodiment is shown in Figure 4. The light-emitting diode includes an AlGaN buffer layer 20 and an N-type semiconductor layer 30 (including an undoped GaN layer 301 and a doped GaN layer) sequentially stacked on the surface of a sapphire substrate 10. Si-doped N-type GaN layer 302), stress relief layer 40, InGaN/GaN multiple quantum well light-emitting layer 50, P-type semiconductor layer 60 (including P-type AlGaN electron blocking layer 601 and Mg-doped P-type GaN layer 602) ;

Wherein, as shown in FIG. 5 , the stress relief layer 40 includes: a first impurity-doped GaN layer (the first impurity is carbon) 401 sequentially stacked on the surface of the Si-doped N-type GaN layer 302 , The undoped GaN layer 402, the InGaN layer 403, and the AlGaN layer 404 grow periodically and alternately, and the cycle period is two cycles.

The method for preparing a light-emitting diode provided in this embodiment includes the following steps:

(1) The growth thickness on the surface of the sapphire substrate 10 at 550°C is AlGaN buffer layer 20.

(2) Perform annealing treatment in an NH ₃ atmosphere, raise the temperature to 1110°C, and allow low-temperature AlGaN to recrystallize into island-shaped seed crystals.

(3) Pass in TMGa (trimethylgallium) and grow a 1 μm thick three-dimensional layer under a pressure of 800mbar.

(4) The temperature is raised to 1150°C, the pressure is reduced to 600mbar, and a layer of non-doped GaN layer 301 is grown with a thickness of 2 μm.

(5) Under the same conditions (the same conditions as step (4)), grow a 2 μm thick Si-doped N-type GaN layer 302, where the Si doping concentration is 3×10 ¹⁹ atoms/cm ³ .

(6) Grow the stress release layer 40: Cool to 900°C, and under a pressure of 300 mbar, first grow a GaN layer doped with the first impurity (the first impurity is carbon) 401 through ion implantation; then, turn off the carbon injection. , grow an undoped GaN layer 402; then grow an InGaN layer 403 and an AlGaN layer 404;

Among them, the GaN layer doped with the first impurity (the first impurity is carbon) 401, the undoped GaN layer 402, the InGaN layer 403 and the AlGaN layer 404 grow periodically, and the number of cycles is 2; and a single doped first The thickness of the impurity GaN layer (the first impurity is carbon) 401 is The thickness of a single undoped GaN layer 402 is /> The thickness of a single InGaN layer 403 is The thickness of a single AlGaN layer 404 is/> The doping concentration of carbon in the GaN layer doped with the first impurity (the first impurity is carbon) 401 is 2×10 ¹⁷ atoms/cm ³ .

(7) Grow the InGaN/GaN multiple quantum well light-emitting layer 50, which is 10 pairs with a total thickness of InGaN/> /GaN/> For the multi-quantum well light-emitting layer, the growth temperature of the GaN barrier layer is 870°C, and the growth temperature of the InGaN well layer is 790°C; the gallium source used in the InGaN well layer and the GaN barrier layer is TEGa (triethylgallium).

(8) Raise the temperature to 1000°C and grow the P-type AlGaN electron blocking layer 601 under a pressure of 200 mbar.

(9) Turn off the aluminum source, keep the conditions the same as step (8), and continue to grow the Mg-doped P-type GaN layer 602. The doping concentration of Mg in the Mg-doped P-type GaN layer 602 is 1×10 ²⁰ atoms/cm ³ .

The total thickness of the P-type AlGaN electron blocking layer 601 and the Mg-doped P-type GaN layer 602 is

Example 2

The structure of the light-emitting diode provided in this embodiment is basically the same as that in Embodiment 1. The difference is that the stress relief layer 40 is shown in FIG. 6 and includes: sequentially stacked on the surface of the Si-doped N-type GaN layer 302. The GaN layer 401 doped with the first impurity (the first impurity is carbon), the InGaN layer 403, and the AlGaN layer 404 are grown periodically and alternately, and the cycle period is three cycles.

The preparation method of the light-emitting diode provided in this embodiment is basically the same as that of Embodiment 1, except that in step (6), the growth temperature of the stress release layer 40 is 850°C and the growth pressure is 200 mbar.

Example 3

The structure of the light-emitting diode provided in this embodiment is basically the same as that in Embodiment 1. The only difference is that the stress relief layer 40 is shown in FIG. 7 and includes: sequentially stacked on the surface of the Si-doped N-type GaN layer 302 The undoped GaN layer 402, the InGaN layer 403, and the AlGaN layer 404 are grown periodically and alternately, and the cycle period is three cycles.

The preparation method of the light-emitting diode provided in this embodiment is basically the same as that of Embodiment 1. The difference is that in step (6), the thickness of the single undoped GaN layer 402 is The thickness of a single InGaN layer 403 is/> The thickness of a single AlGaN layer 404 is/>

Example 4

The structure of the light-emitting diode provided in this embodiment is basically the same as that in Embodiment 1. The only difference is that the stress relief layer 40 is shown in FIG. 8 and includes: sequentially stacked on the surface of the Si-doped N-type GaN layer 302 The GaN layer doped with the first impurity (the first impurity is carbon) 401, the undoped GaN layer 402, and the AlGaN layer 404 are formed. The above layers grow periodically and alternately, and the cycle period is four cycles.

The preparation method of the light-emitting diode provided in this embodiment is basically the same as that in Embodiment 1. The difference is that in step (6), the thickness of a single GaN layer doped with the first impurity (the first impurity is carbon) 401 is The thickness of a single undoped GaN layer 402 is /> The thickness of a single AlGaN layer 404 is/> And the carbon doping concentration in the GaN layer doped with the first impurity (the first impurity is carbon) 401 is 5×10 ¹⁷ atoms/cm ³ .

Example 5

The light-emitting diode provided in this embodiment includes: a substrate 10, and an AlGaN buffer layer 20 and an N-type semiconductor layer 30 (including an undoped GaN layer 301 and a Si-doped N-type GaN layer) sequentially stacked on the surface of the substrate 10. layer 302), stress relief layer 40, InGaN/GaN multiple quantum well light-emitting layer 50, and P-type semiconductor layer 60 (including P-type AlGaN electron blocking layer 601 and Mg-doped P-type GaN layer 602).

The stress relief layer in this embodiment includes a first sub-layer and a second sub-layer, wherein the first sub-layer is a periodic structure with a period number of 5, and the second sub-layer is located between the first sub-layer and the multi-quantum well to emit light. between layers 50.

As shown in FIG. 9 , the first sub-layer in the stress relief layer 40 includes alternately stacked GaN layers 401 doped with the first impurity and undoped GaN layers 402 ; the second sub-layer, namely the AlGaN layer 404 (is a single layer structure) is located between the undoped GaN layer 402 and the multi-quantum well light emitting layer 50 .

In this embodiment, the first impurity in the GaN layer 401 doped with the first impurity is a carbon impurity, and the carbon doping concentration is 3×10 ¹⁷ atoms/cm ³ .

Example 6

The structure of the light-emitting diode provided in this embodiment is basically the same as that in Embodiment 5. The only difference is that the first sub-layer in the stress relief layer 40 is shown in FIG. 10 and includes alternately stacked GaN doped with the first impurity. layer 401 and InGaN layer 403; the second sub-layer, AlGaN layer 404 (which is a single-layer structure), is located between the doped InGaN layer 403 and the multi-quantum well light-emitting layer 50.

Example 7

The structure of the light-emitting diode provided in this embodiment is basically the same as that in Embodiment 5. The only difference is that the first sub-layer in the stress relief layer 40 is shown in Figure 11 and includes alternately stacked undoped GaN layers 402. and InGaN layer 403; the second sublayer, namely AlGaN layer 404 (a single-layer structure), is located between the doped InGaN layer 403 and the multi-quantum well light-emitting layer 50.

Example 8

The structure of the light-emitting diode provided in this embodiment is basically the same as that in Embodiment 5. The only difference is that the first sub-layer in the stress relief layer 40 is shown in Figure 12 and includes a GaN layer 401 doped with the first impurity. The doped GaN layer 402 and the InGaN layer 403; the second sub-layer, the AlGaN layer 404 (which is a single-layer structure), is located between the doped InGaN layer 403 and the multi-quantum well light-emitting layer 50.

Although the present invention has been illustrated and described with specific embodiments, it should be realized that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit it; those of ordinary skill in the art should understand that: Without departing from the spirit and scope of the present invention, the technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features thereof may be equivalently substituted; however, these modifications or substitutions shall not make the corresponding technical solutions essentially depart from the scope of the technical solutions of the various embodiments of the present invention; therefore, it is meant that all such substitutions and modifications falling within the scope of the present invention are included in the appended claims.

Claims (13)

1. The light-emitting diode is characterized by comprising a substrate, and a buffer layer, an N-type semiconductor layer, a stress release layer, a multiple quantum well light-emitting layer and a P-type semiconductor layer which are sequentially laminated on the surface of the substrate;

wherein the stress relief layer comprises a first sub-layer and a second sub-layer;

the first sub-layer is of a periodic structure;

the second sub-layer is of a single-layer structure, and the second sub-layer is an AlGaN layer.

2. The led of claim 1, wherein the alternating period of the first sub-layer is 2-5 periods.

3. The light emitting diode of claim 1, wherein the first sub-layer comprises at least two of a GaN layer doped with a first impurity, an undoped GaN layer, and an InGaN layer.

4. A light emitting diode according to claim 3 comprising at least one of the following features (1) to (3):

(1) The GaN layer doped with the first impurityIs of the thickness of

(2) The thickness of the undoped GaN layer is

(3) The thickness of the InGaN layer is

5. The light-emitting diode according to claim 3, wherein the first sub-layer includes a GaN layer doped with the first impurity and an undoped GaN layer arranged in a periodically alternating stack;

alternatively, the first sub-layer includes a GaN layer doped with a first impurity and an InGaN layer arranged in a periodically alternating stack;

alternatively, the first sub-layer includes undoped GaN layers and InGaN layers that are alternately stacked periodically;

alternatively, the first sub-layer includes a GaN layer doped with the first impurity, an undoped GaN layer, and an InGaN layer, which are alternately stacked in a periodic manner.

6. A light emitting diode according to claim 3 wherein the first impurity in the first impurity doped GaN layer comprises carbon and/or silicon;

preferably, the carbon has a doping concentration of 1×10 ¹⁷ ～5×10 ¹⁷ atoms/cm ³ ；

Preferably, the doping concentration of the silicon is 1×10 ¹⁸ ～5×10 ¹⁸ atoms/cm ³ 。

7. The led of claim 1, wherein the AlGaN layer has a thickness of

8. The led of claim 1, wherein said AlGaN layer is further doped with silicon;

preferably, the doping concentration of the silicon is 1×10 ¹⁸ ～5×10 ¹⁸ atoms/cm ³ 。

9. The light emitting diode of any one of claims 1-8, wherein the first sub-layer is disposed on the N-type semiconductor layer and the second sub-layer is disposed between the first sub-layer and the multiple quantum well light emitting layer.

10. The light emitting diode of any one of claims 1 to 8, wherein the first sub-layer and the second sub-layer are arranged in a periodic stack;

preferably, the alternating period of the first sub-layer and the second sub-layer is 2 to 5 periods.

11. The light-emitting diode according to claim 10, wherein the stress release layer comprises a GaN layer doped with a first impurity, an undoped GaN layer, an InGaN layer, and an AlGaN layer which are sequentially stacked and disposed on the N-type semiconductor layer in a periodic alternating manner;

or the stress release layer comprises a GaN layer doped with a first impurity, an InGaN layer and an AlGaN layer which are sequentially stacked and arranged on the N-type semiconductor layer in a periodical and alternating manner;

or the stress release layer comprises an undoped GaN layer, an InGaN layer and an AlGaN layer which are sequentially stacked and arranged on the N-type semiconductor layer in a periodical and alternating manner;

alternatively, the stress release layer includes a GaN layer doped with the first impurity, an undoped GaN layer, and an AlGaN layer sequentially stacked and disposed on the N-type semiconductor layer in a periodic alternating manner.

12. The light emitting diode of claim 1, wherein the N-type semiconductor layer comprises an undoped GaN layer and/or an N-type GaN layer doped with a second impurity;

preferably, the second impurity includes Si;

preferably, the doping concentration of the second impurity is 1×10 ¹⁹ ～5×10 ¹⁹ atoms/cm ³ 。

13. The light emitting diode of claim 1, wherein the P-type semiconductor layer comprises a third impurity doped P-type GaN layer;

preferably, the third impurity comprises Mg;

preferably, the doping concentration of the third impurity is 1×10 ¹⁹ ～1×10 ²¹ atoms/cm ³ 。