CN113140657B - Ultraviolet LED epitaxial structure and preparation method thereof - Google Patents

Abstract

The invention discloses an ultraviolet LED epitaxial structure, comprising a substrate, and a low-temperature AlN layer, a high-temperature AlN layer, an intrinsic AlGaN layer, a silane-doped n-type AlGaN layer, and a silane-doped silane layer, which are sequentially located on the substrate from bottom to top. n-doped AlGaN/AlN superlattice layer, quantum well region-1, superlattice SL region-1, quantum well region-2, superlattice SL region-2, quantum well region-3, superlattice SL Region-3, quantum well region-n, superlattice SL region-n, p-type AlGaN layer and magnesium-doped p++-type BAlGaN layer, through the design and growth method of the present invention, can meet the requirements for various ultraviolet The integration and unification of band requirements greatly simplifies the subsequent packaging steps, improves the overall reliability of the chip, and realizes the multi-purpose function of one core.

Description

A kind of ultraviolet LED epitaxial structure and preparation method thereof

technical field

The invention relates to the technical field of semiconductor electronic information, and more particularly to an ultraviolet LED epitaxial structure and a preparation method thereof.

Background technique

With the progress of science and technology and the development of new energy sources, solid-state LED lighting will become the trend of future lighting in the world. Because LED has the advantages of energy saving, environmental protection, safety, long life, low consumption and low heat, it has been widely used in traffic lights, Traffic signal lights, landscape decorative lights, display screens, car tail lights, mobile phone backlights, sterilization and other fields. At present, the LEDs on the market are mainly blue-green light, followed by red and yellow light, and there are few LED products of violet light and deep ultraviolet light, mainly due to the difficulty of manufacturing high-power deep ultraviolet LEDs and low luminous efficiency. With the development of LED applications, the market demand for UV LEDs is increasing, and they are widely used in medical equipment, medical measurement, sanitation and disinfection, currency detection and counting inspection equipment, anti-counterfeiting industry, biometric security testing, covering medical, health, Finance, biology, detection, public safety and other aspects. Under the current LED background, the purple light market has a very broad prospect.

At present, the epitaxial growth technology of violet LEDs is not mature enough. On the one hand, it is limited by the characteristics of ultraviolet light growth materials, on the other hand, it is affected by the energy band structure and design structure of ultraviolet LEDs, and it is also affected by the influence of preparation and growth methods. With the diversity of market demand for UV chip products, UV chips with various wavelengths such as 200-280nm, 350-360nm, and 380-395nm have a significant increase in demand. The traditional application is to package multiple different chip wavelengths together. To the mixed effect, the multi-wavelength chip package increases the cost and reduces the reliability, so how to prepare high-power composite wavelength UV LED chips has become a very urgent requirement.

SUMMARY OF THE INVENTION

In view of this, the present invention provides an ultraviolet LED epitaxial structure and a preparation method thereof. Through the design and preparation method of the present invention, the integration and unification of various ultraviolet band requirements in practical applications can be met, and subsequent packaging is greatly simplified. It also improves the overall reliability of the chip, realizes the multi-purpose function of one chip, improves the comprehensive function and competitiveness of the ultraviolet LED chip, and can meet industrial-grade applications on a large scale.

In order to achieve the above object, the present invention adopts the following technical solutions:

An ultraviolet LED epitaxial structure, comprising a substrate, an intrinsic AlGaN layer, an n-type AlGaN layer, an n-doped AlGaN/AlN superlattice layer, a quantum well region, and a superlattice SL which are sequentially located on the substrate from bottom to top region, p-type AlGaN layer and p++-type BAlGaN layer.

Preferably, the above-mentioned substrate is a sapphire substrate or a silicon substrate.

Preferably, the above-mentioned ultraviolet LED epitaxial structure further includes an AlN layer disposed between the substrate layer and the intrinsic AlGaN layer;

The AlN layer includes a low temperature AlN layer and a high temperature AlN layer; the high temperature AlN layer is located above the low temperature AlN layer; the thickness of the low temperature AlN layer is 10 nm; and the thickness of the high temperature AlN layer is 200 nm.

Preferably, the thickness of the above-mentioned intrinsic AlGaN layer is 100 nm; the thickness of the n-type AlGaN layer is 100-300 nm.

Further, the above-mentioned n-type AlGaN layer is an n-type AlGaN layer doped with silane; the doping amount of silane is 10 ^20±1 cm ³ .

Preferably, the above-mentioned n-doped AlGaN/AlN superlattice layer is composed of AlGaN and AlN growing alternately for 10-15 cycles; wherein the thickness of each layer of AlGaN is 2-5nm, and the thickness of each layer of AlN is 2nm.

Further, the above-mentioned n-doped AlGaN/AlN superlattice layer is an n-doped AlGaN/AlN superlattice layer doped with silane; the silane doping amount is 10 ^20±1 cm ³ .

Preferably, the quantum well region and the superlattice SL region are respectively provided with n layers, n≥3, and the quantum well region and the superlattice SL region are alternately stacked.

Preferably, the quantum well region includes quantum well region-1, quantum well region-2, quantum well region-3 and quantum well region-n;

The quantum well region-1 includes a quantum well region-a of 3-4 periods; the quantum well region-a includes two layers of Al _x Ga _1-x N quantum barrier layers and two layers of Al _x Ga _1-x N quantum barrier layers. The InGaN quantum well layer in between, 0<x<1; the thickness of the AlxGa1 _{- xN} quantum barrier layer is 12-15nm; the thickness of the InGaN quantum well layer is 2-3nm;

The quantum well region-2 includes a quantum well region-b of 3-4 periods; the quantum well region-b includes two layers of _{AlyGa1 -yN} quantum barrier layers and two layers of _{AlyGa1 -yN} quantum barrier layers. The AlInGaN quantum well layer between them, x<y<1; the thickness of the _{AlyGa 1-yN} quantum barrier layer is 12-15nm; the thickness of the AlInGaN quantum well layer is 2-3nm;

Quantum well region-3 includes 3-4 periods of quantum well region-c; quantum well region-c includes two BAlGaN quantum barrier layers and an AlGaN quantum well layer located between the two BAlGaN quantum barrier layers; BAlGaN quantum barrier layer The thickness of the AlGaN quantum well layer is 12-15nm; the thickness of the AlGaN quantum well layer is 2-3nm;

Quantum well region-n includes 3-4 periods of quantum well region-d; quantum well region-d includes two BInAlGaN quantum barrier layers and an AlInGaN quantum well layer located between the two BInAlGaN quantum barrier layers; The thickness is 12-15nm; the thickness of the AlInGaN quantum well layer is 2-3nm.

Quantum wells of different materials determine different light-emitting wavelengths, and several layers of different quantum wells generate light of different wavelengths, which can realize the simultaneous excitation of multiple different ultraviolet wavelengths in the same epitaxial layer and the same chip, and realize multiple The integrated application of different UV wavelengths in the same chip.

Preferably, the above-mentioned superlattice SL region includes superlattice SL region-1, superlattice SL region-2, superlattice SL region-3 and superlattice SL region-n;

The superlattice SL region-1 includes a 4-6 period superlattice SL region-a; the superlattice SL region-a includes an _{AlyGa1 -yN} layer and an AlInGaN layer above it, x<y<1; the thickness of the _{AlyGa1 -yN} layer is 2-3nm; the thickness of the AlInGaN layer is 2-3nm;

The superlattice SL region-2 includes 4-6 periods of the superlattice SL region-b; the superlattice SL region-b includes a BAlGaN layer and an AlGaN layer above it; the thickness of the BAlGaN layer is 2-3 nm; the AlGaN layer The thickness of the layer is 2-3 nm;

Superlattice SL region-3 includes 4-6 periods of superlattice SL region-c; superlattice SL region-c includes a BInAlGaN layer and an AlInGaN layer above it; the thickness of the BInAlGaN layer is 2-3 nm; AlInGaN The thickness of the layer is 2-3 nm;

The superlattice SL region-n includes 4-6 periods of the superlattice SL region-d; the superlattice SL region-d includes an AlGaN layer and an AlInGaN layer above it; the AlGaN layer has a thickness of 2 -3nm; the thickness of the AlInGaN layer is 2-3nm.

The purpose of setting different superlattices in the middle of quantum wells of different materials is to reduce lattice mismatch and strain force of different quantum well materials, which is conducive to better connection and material matching of different layers of materials.

Preferably, the thickness of the p-type AlGaN layer is 500 nm; the thickness of the p++-type BAlGaN layer is 3-5 nm.

Further, the above-mentioned p-type AlGaN layer is a magnesium-doped p-type AlGaN layer, and the magnesium doping amount is 10 ^19±1 cm ³ ; the above-mentioned p++-type BAlGaN layer is a magnesium-doped p++-type BAlGaN layer, and the doping amount of magnesium is is 10 ^{21 ± 1} cm ³ .

Another object of the present invention is to provide a method for preparing the above-mentioned ultraviolet LED epitaxial structure, using sapphire or silicon substrate and other material substrates as growth substrates, performing heteroepitaxial growth, using MOCVD (metal organic chemical vapor deposition) technology to complete the entire epitaxy process;

The specific method is as follows:

(1) A layer of low-temperature AlN layer is grown on the substrate;

(2) growing a high temperature AlN layer on the low temperature AlN layer;

(3) growing an intrinsic AlGaN layer on the high temperature AlN layer;

(4) growing an n-type AlGaN layer on the intrinsic AlGaN layer;

(5) growing an n-doped AlGaN/AlN superlattice layer on the n-type AlGaN layer;

(6) Growth of a quantum well region-1 on the n-doped AlGaN/AlN superlattice layer

(7) A layer of superlattice SL-1 is grown on the quantum well region-1;

(8) A layer of quantum well region-2 is grown on the superlattice SL-1;

(9) growing a layer of superlattice SL-2 on the quantum well region-2;

(10) A layer of quantum well region-3 is grown on the superlattice SL-2;

(11) A layer of superlattice SL-3 is grown on the quantum well region-3;

(12) A layer of quantum well region-n is grown on the superlattice SL-3;

(13) growing a layer of superlattice SL-n on the quantum well region-n;

(14) growing a p-type AlGaN layer on the superlattice SL-n;

(15) A p++-type BAlGaN layer is grown on the p-type AlGaN layer.

Preferably, in the present invention, trimethylgallium (TMGa), triethylgallium (TEGa), triethylboron (TEB), trimethylaluminum (TMAl) and ammonia ( _NH3 ) silane (SiH4) are used And magnesium locene (Cp2Mg), nitrogen, hydrogen provide gallium source, aluminum source, boron source, and nitrogen source, silicon source, magnesium source and carrier gas required for growth respectively.

As can be seen from the above-mentioned technical solutions, compared with the prior art, the present invention has the following beneficial effects:

1. Through the design and growth method of the present invention, the integration and unification of various ultraviolet band requirements in practical applications can be met, the subsequent packaging steps are simplified to a great extent, and the overall reliability of the chip is improved. Function;

2. Through the quantum well-1 area, the quantum well-2 area and the quantum well-3 area or more through the quantum well-n area, through the quantum well material that does not pass through, different wavelengths can be combined to emit light; by adding different wavelengths The periodic material SL (superlattice) can reduce the material adaptation problem of various quantum well regions, improve the overall crystal quality of the light-emitting region, and realize the same epitaxial structure;

3. The emission of different wavelengths can be realized at the same time, especially 200-250nm, 260-280nm, 350-370nm, 380-395nm.. These applications have a wide range of wavelengths, and often need more than two wavelengths at the same time. The process of encapsulating subsequent chips with different wavelengths is reduced, and the integration of chips is realized.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to the provided drawings without creative work.

1 is a schematic structural diagram of an epitaxial overall structure diagram of an ultraviolet LED of the present invention;

2 is a schematic structural diagram of the quantum well region-1 of the present invention;

Fig. 3 accompanying drawing is the structure schematic diagram of quantum well region-2 of the present invention;

4 is a schematic structural diagram of the quantum well region-3 of the present invention;

Figure 5 is a schematic diagram of the quantum well region-n structure of the present invention;

6 is a schematic diagram of the structure of the superlattice SL-1 region of the present invention;

7 is a schematic diagram of the structure of the superlattice SL-2 region of the present invention;

8 is a schematic diagram of the structure of the superlattice SL-3 region of the present invention;

FIG. 9 is a schematic diagram of the structure of the superlattice SL-n region of the present invention.

Among them, in the figure:

1-AlxGa1 _{- XN} quantum barrier layer; 2-InGaN quantum well layer; 3- _{AlyGa1 -yN} quantum barrier layer (y>x); 4-AlInGaN quantum well layer; 5-BAlGaN quantum barrier 6-AlGaN quantum well layer; 7-BInAlGaN quantum barrier layer; 8- _{AlyGa1 -yN} layer; 9-AlInGaN layer; 10-BAlGaN layer; 11-AlGaN layer; 12-BInAlGaN layer.

Detailed ways

The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The embodiment of the present invention discloses an ultraviolet LED epitaxial structure, which includes a substrate, an intrinsic AlGaN layer, an n-type AlGaN layer, an n-doped AlGaN/AlN superlattice layer, and a quantum well that are sequentially located on the substrate from bottom to top. region, superlattice SL region, p-type AlGaN layer and p++-type BAlGaN layer.

In order to further optimize the above technical solution, the substrate is a sapphire substrate or a silicon substrate;

In order to further optimize the above technical solution, the ultraviolet LED epitaxial structure further includes an AlN layer disposed between the substrate layer and the intrinsic AlGaN layer;

The AlN layer includes a low-temperature AlN layer and a high-temperature AlN layer; the high-temperature AlN layer is located above the low-temperature AlN layer; the thickness of the low-temperature AlN layer is 10 nm; the thickness of the high-temperature AlN layer is 200 nm;

In order to further optimize the above technical scheme, the thickness of the intrinsic AlGaN layer is 100nm; the thickness of the n-type AlGaN layer is 100-300nm;

In order to further optimize the above technical solution, the n-type AlGaN layer is an n-type AlGaN layer doped with silane; the doping amount of silane is 10 ^20±1 cm ³ ;

In order to further optimize the above technical scheme, the n-doped AlGaN/AlN superlattice layer is composed of AlGaN and AlN alternately grown for 10-15 cycles; the thickness of each layer of AlGaN is 2-5nm, and the thickness of each layer of AlN is 2nm;

In order to further optimize the above technical solution, the above n-doped AlGaN/AlN superlattice layer is an n-doped AlGaN/AlN superlattice layer doped with silane; the silane doping amount is 10 ^20±1 cm ³ ;

In order to further optimize the above technical solution, the quantum well region and the superlattice SL region are respectively provided with n layers, n≥3, and the quantum well region and the superlattice SL region are alternately stacked;

In order to further optimize the above technical solution, the quantum well region includes quantum well region-1, quantum well region-2, quantum well region-3 and quantum well region-n;

The quantum well region-1 includes a quantum well region-a of 3-4 periods; the quantum well region-a includes two layers of Al _x Ga _1-x N quantum barrier layers and two layers of Al _x Ga _1-x N quantum barrier layers. The InGaN quantum well layer in between, 0<x<1; the thickness of the AlxGa1 _{- xN} quantum barrier layer is 12-15nm; the thickness of the InGaN quantum well layer is 2-3nm;

The quantum well region-2 includes a quantum well region-b of 3-4 periods; the quantum well region-b includes two layers of _{AlyGa1 -yN} quantum barrier layers and two layers of _{AlyGa1 -yN} quantum barrier layers. The AlInGaN quantum well layer between them, x<y<1; the thickness of the _{AlyGa 1-yN} quantum barrier layer is 12-15nm; the thickness of the AlInGaN quantum well layer is 2-3nm;

Quantum well region-3 includes 3-4 periods of quantum well region-c; quantum well region-c includes two BAlGaN quantum barrier layers and an AlGaN quantum well layer located between the two BAlGaN quantum barrier layers; BAlGaN quantum barrier layer The thickness of the AlGaN quantum well layer is 12-15nm; the thickness of the AlGaN quantum well layer is 2-3nm;

Quantum well region-n includes 3-4 periods of quantum well region-d; quantum well region-d includes two BInAlGaN quantum barrier layers and an AlInGaN quantum well layer located between the two BInAlGaN quantum barrier layers; The thickness is 12-15nm; the thickness of the AlInGaN quantum well layer is 2-3nm;

In order to further optimize the above technical solution, the superlattice SL region includes superlattice SL region-1, superlattice SL region-2, superlattice SL region-3 and superlattice SL region-n;

The superlattice SL region-1 includes a 4-6 period superlattice SL region-a; the superlattice SL region-a includes an _{AlyGa1 -yN} layer and an AlInGaN layer above it, x<y<1; the thickness of the _{AlyGa1 -yN} layer is 2-3nm; the thickness of the AlInGaN layer is 2-3nm;

The superlattice SL region-2 includes 4-6 periods of the superlattice SL region-b; the superlattice SL region-b includes a BAlGaN layer and an AlGaN layer above it; the thickness of the BAlGaN layer is 2-3 nm; the AlGaN layer The thickness of the layer is 2-3 nm;

Superlattice SL region-3 includes 4-6 periods of superlattice SL region-c; superlattice SL region-c includes a BInAlGaN layer and an AlInGaN layer above it; the thickness of the BInAlGaN layer is 2-3 nm; AlInGaN The thickness of the layer is 2-3 nm;

The superlattice SL region-n includes 4-6 periods of the superlattice SL region-d; the superlattice SL region-d includes an AlGaN layer and an AlInGaN layer above it; the AlGaN layer has a thickness of 2 -3nm; the thickness of the AlInGaN layer is 2-3nm.

In order to further optimize the above technical solution, the thickness of the p-type AlGaN layer is 500nm; the thickness of the p++-type BAlGaN layer is 3-5nm;

In order to further optimize the above technical solution, the p-type AlGaN layer is a magnesium-doped p-type AlGaN layer, and the magnesium doping amount is 10 ^19±1 cm ³ ; the p++-type BAlGaN layer is a magnesium-doped p++-type BAlGaN layer, and the magnesium The doping amount was 10 ^21±1 cm ³ .

Example 1

Referring to FIG. 1 , this embodiment provides an ultraviolet LED epitaxial structure, including a substrate, and a low-temperature AlN layer, a high-temperature AlN layer, an intrinsic AlGaN layer, and a silane-doped n-type AlGaN layer on the substrate sequentially from bottom to top layer, silane-doped n-doped AlGaN/AlN superlattice layer, quantum well region-1, superlattice SL region-1, quantum well region-2, superlattice SL region-2, quantum well region-3 , a superlattice SL region-3, a quantum well region-n, a superlattice SL region-n, a p-type AlGaN layer and a magnesium-doped p++-type BAlGaN layer.

In this embodiment, the thickness of the low temperature AlN layer is 10 nm; the thickness of the high temperature AlN layer is 200 nm;

The thickness of the AlGaN layer is 100 nm; the thickness of the n-type AlGaN layer doped with silane is 200 nm; the doping amount of silane is 10 ^{20 ±1} cm ³ ;

The n-doped AlGaN/AlN superlattice layer doped with silane is composed of AlGaN and AlN alternately grown for 10 cycles; the thickness of each layer of AlGaN is 2nm, and the thickness of each layer of AlN is 2nm; the doping amount of silane is 10 ^{20±1 cm3} ;

The quantum well region-1 includes 4 periods of quantum well region-a, the thickness of the Al _x Ga _1-x N quantum barrier layer is 12 nm; the thickness of the InGaN quantum well layer is 2 nm, 0<x<1;

The quantum well region-2 includes 4 periods of quantum well region-b, the thickness of the _{AlyGa1 -yN} quantum barrier layer is 12nm; the thickness of the AlInGaN quantum well layer is 2nm, x<y<1;

The quantum well region-3 includes 4 periods of quantum well region-c, the thickness of the BAlGaN quantum barrier layer is 12 nm; the thickness of the AlGaN quantum well layer is 2 nm;

The quantum well region-n includes 4 periods of quantum well region-d, the thickness of the BInAlGaN quantum barrier layer is 12nm; the thickness of the AlInGaN quantum well layer is 2nm;

The superlattice SL region-1 includes a 6-period superlattice SL region-a, the thickness of the _{AlyGa1 -yN} layer is 2nm, x<y<1; the thickness of the AlInGaN layer is 2nm;

The superlattice SL region-2 includes 6 periods of the superlattice SL region-b, and the thickness of the BAlGaN layer is 2 nm; the thickness of the AlGaN layer is 2 nm;

The superlattice SL region-3 includes 6 periods of the superlattice SL region-c, and the thickness of the BInAlGaN layer is 2 nm; the thickness of the AlInGaN layer is 2 nm;

The superlattice SL region-n includes 6 periods of the superlattice SL region-d, and the thickness of the AlGaN layer is 2 nm; the thickness of the AlInGaN layer is 2 nm;

The thickness of the magnesium-doped p-type AlGaN layer is 500 nm, and the magnesium doping amount is 10 ^19±1 cm ³ ; the thickness of the magnesium-doped p++ type BAlGaN layer is 3 nm, and the magnesium doping amount is 10 ^{21 ± 1} cm ³ .

Example 2

This embodiment provides an ultraviolet LED epitaxial structure, including a substrate, and a low-temperature AlN layer, a high-temperature AlN layer, an intrinsic AlGaN layer, a silane-doped n-type AlGaN layer, a doped silane layer, and a low-temperature AlN layer on the substrate in order from bottom to top Silane n-doped AlGaN/AlN superlattice layer, quantum well region-1, superlattice SL region-1, quantum well region-2, superlattice SL region-2, quantum well region-3, superlattice SL region-3, quantum well region-n, superlattice SL region-n, p-type AlGaN layer and magnesium-doped p++-type BAlGaN layer.

In this embodiment, the thickness of the low temperature AlN layer is 10 nm; the thickness of the high temperature AlN layer is 200 nm;

The thickness of the characteristic AlGaN layer is 100 nm; the thickness of the n-type AlGaN layer doped with silane is 100 nm; the doping amount of silane is 10 ^{20 ±1} cm ³ ;

The n-doped AlGaN/AlN superlattice layer doped with silane is composed of AlGaN and AlN alternately grown for 10 cycles; the thickness of each layer of AlGaN is 5nm, and the thickness of each layer of AlN is 2nm; the doping amount of silane is 10 ^{20±1 cm3} ;

The quantum well region-1 includes three periods of quantum well region-a, the thickness of the Al _x Ga _1-x N quantum barrier layer is 15 nm; the thickness of the InGaN quantum well layer is 2 nm, 0<x<1;

The quantum well region-2 includes three periods of quantum well region-b, the thickness of the _{AlyGa1 -yN} quantum barrier layer is 15nm; the thickness of the AlInGaN quantum well layer is 2nm, x<y<1;

The quantum well region-3 includes three periods of quantum well region-c, the thickness of the BAlGaN quantum barrier layer is 15nm; the thickness of the AlGaN quantum well layer is 2nm;

The quantum well region-n includes three periods of quantum well region-d, the thickness of the BInAlGaN quantum barrier layer is 15nm; the thickness of the AlInGaN quantum well layer is 2nm;

The superlattice SL region-1 includes a 4-period superlattice SL region-a, the thickness of the AlyGa1 _{-yN layer} is 3 nm, and x<y<1; the thickness of the AlInGaN layer is 3 nm;

The superlattice SL region-2 includes 4 periods of the superlattice SL region-b, and the thickness of the BAlGaN layer is 3 nm; the thickness of the AlGaN layer is 3 nm;

The superlattice SL region-3 includes 4 periods of the superlattice SL region-c, and the thickness of the BInAlGaN layer is 3 nm; the thickness of the AlInGaN layer is 3 nm;

The superlattice SL region-n includes 4 periods of the superlattice SL region-d, and the thickness of the AlGaN layer is 3 nm; the thickness of the AlInGaN layer is 3 nm;

The thickness of the magnesium-doped p-type AlGaN layer is 500 nm, and the magnesium doping amount is 10 ^19±1 cm ³ ; the thickness of the magnesium-doped p++ type BAlGaN layer is 5 nm, and the magnesium doping amount is 10 ^{21 ± 1} cm ³ .

Example 3

This embodiment provides an ultraviolet LED epitaxial structure, including a substrate, and a low-temperature AlN layer, a high-temperature AlN layer, an intrinsic AlGaN layer, a silane-doped n-type AlGaN layer, a doped silane layer, and a low-temperature AlN layer on the substrate in order from bottom to top Silane n-doped AlGaN/AlN superlattice layer, quantum well region-1, superlattice SL region-1, quantum well region-2, superlattice SL region-2, quantum well region-3, superlattice SL region-3, quantum well region-n, superlattice SL region-n, p-type AlGaN layer and magnesium-doped p++-type BAlGaN layer.

In this embodiment, the thickness of the low temperature AlN layer is 10 nm; the thickness of the high temperature AlN layer is 200 nm;

The thickness of the AlGaN layer is 100 nm; the thickness of the n-type AlGaN layer doped with silane is 300 nm; the doping amount of silane is 10 ^{20 ±1} cm ³ ;

The n-doped AlGaN/AlN superlattice layer doped with silane is composed of AlGaN and AlN alternately grown for 10 cycles; the thickness of each layer of AlGaN is 2nm, and the thickness of each layer of AlN is 2nm; the doping amount of silane is 10 ^{20±1 cm3} ;

The quantum well region-1 includes 4 periods of quantum well region-a, the thickness of the Al _x Ga _1-x N quantum barrier layer is 13 nm; the thickness of the InGaN quantum well layer is 2 nm, 0<x<1;

The quantum well region-2 includes 4 periods of quantum well region-b, the thickness of the _{AlyGa1 -yN} quantum barrier layer is 13nm; the thickness of the AlInGaN quantum well layer is 2nm, x<y<1;

The quantum well region-3 includes 4 periods of quantum well region-c, the thickness of the BAlGaN quantum barrier layer is 14 nm; the thickness of the AlGaN quantum well layer is 2 nm;

The quantum well region-n includes 4 periods of quantum well region-d, the thickness of the BInAlGaN quantum barrier layer is 14nm; the thickness of the AlInGaN quantum well layer is 2nm;

The superlattice SL region-1 includes 5 periods of the superlattice SL region-a, the thickness of the AlyGa1 _{-yN layer} is 3 nm, x<y<1; the thickness of the AlInGaN layer is 2 nm;

The superlattice SL region-2 includes 5 periods of the superlattice SL region-b, and the thickness of the BAlGaN layer is 3 nm; the thickness of the AlGaN layer is 2 nm;

The superlattice SL region-3 includes 5 periods of the superlattice SL region-c, and the thickness of the BInAlGaN layer is 3 nm; the thickness of the AlInGaN layer is 2 nm;

The superlattice SL region-n includes 5 periods of the superlattice SL region-d, and the thickness of the AlGaN layer is 3 nm; the thickness of the AlInGaN layer is 2 nm;

The thickness of the magnesium-doped p-type AlGaN layer is 500 nm, and the magnesium doping amount is 10 ^19±1 cm ³ ; the thickness of the magnesium-doped p++ type BAlGaN layer is 4 nm, and the magnesium doping amount is 10 ^{21 ± 1} cm ³ .

Example 4

The preparation method of the ultraviolet LED epitaxial structure in the above-mentioned embodiments 1-3 adopts the metal organic compound chemical vapor deposition (MOCVD) epitaxial growth technology, and adopts trimethyl gallium (TMGa), triethyl gallium (TEGa), triethyl boron (TEB), trimethylaluminum (TMAl) and ammonia (NH ₃ ) silane (SiH ₄ ) and magnesium dimethylocene (Cp2Mg), nitrogen, hydrogen provide the sources of gallium, aluminum, boron, and Nitrogen source, silicon source, magnesium source and carrier gas, the specific preparation method is as follows:

(1) After cleaning the sapphire substrate, put it into MOCVD equipment and bake at 1200°C for 15min;

(2) Cool down to 600°C, grow a low-temperature AlN layer by feeding trimethylaluminum (TMAl) and ammonia gas (NH ₃ ), the growth pressure is 220torr, then heat up to 1060°C, and continuously feed trimethylaluminum Aluminum (TMAl) and ammonia (NH ₃ ), grow a high temperature AlN layer, and the growth pressure is 220torr;

(3) the temperature is raised to 1070°C, and at 250torr, trimethylgallium (TMGa), trimethylaluminum (TMAl) and ammonia gas ( _NH3 ) are introduced to grow an intrinsic low temperature GaAlN layer;

(4) Keep the temperature unchanged, continue to grow a layer of n-type AlGaN layer doped with silane, and the growth pressure is 150torr;

(5) Cool down to 1060°C, and at 150torr, feed triethylgallium (TMGa), trimethylaluminum (TMAl) and ammonia (NH ₃ ) to grow a layer of silane-doped n-type AlGaN/AlN supercrystal Lattice layer, according to needs, repeat the growth of multiple cycles of AlGaN/AlN superlattice structure;

(6) Cool down to about 1050 °C, grow a layer of Al _X Ga _1-X N quantum barrier layer at 300 torr, then cool down to 800-900 ° C, grow a layer of InGaN quantum well layer, and then grow a layer of Al _X Ga _1-X N quantum barrier layer, repeat the growth for multiple cycles as needed to complete the growth of quantum well region-1;

(7) Keeping the temperature unchanged, at 260torr, grow an _{AlyGa1 -yN} layer, then cool down to 1045°C, grow an AlInGaN layer, and repeat the growth for multiple cycles as needed to form a superlattice SL -zone 1;

(8) Keep the temperature not far, at 300torr, grow a layer of _{AlyGa1 -yN quantum} barrier layer, then cool down to 800-1000℃, grow a layer of AlInGaN quantum well layer, and then grow a layer of _{AyGa1 -y} N quantum barrier layer, repeat the growth for multiple cycles as needed to complete the growth of quantum well region-2;

(9) Raising the temperature to 1060°C, at 300torr, grow a layer of BAlGaN layer, then grow a layer of AlGaN layer, and repeat the growth for multiple cycles as needed to form a superlattice SL-2 region;

(10) The temperature is raised to about 1070°C, and at 300torr, a layer of BAlGaN quantum barrier layer is grown, then a layer of AlGaN quantum well layer is grown, and then a layer of BAlGaN quantum barrier layer is grown, and repeated growth cycles as needed to complete the quantum Well region-3 growth;

(11) Raising the temperature to 1080°C, at 300torr, grow a BInAlGaN layer, then grow an AlInGaN layer, and repeat the growth for multiple cycles as needed to form a superlattice SL-3 region;

(12) Cool down to about 1070°C, and at 300torr, grow a BInAlGaN quantum barrier layer, then grow an AlInGaN quantum well layer, and then grow a BInAlGaN quantum barrier layer, and repeat the growth for multiple cycles as needed to complete the quantum Well region-n growth;

(13) At a temperature of 1070 °C and 300 torr, grow an AlGaN layer, then grow an AlInGaN layer, and repeat the growth for multiple cycles as needed to form a superlattice SL-n region;

(14) The temperature is lowered to 1030° C., and a p-type AlGaN layer doped with magnesium is grown at 150 torr.

(15) Keeping the temperature unchanged, a layer of magnesium-doped p++ type BAlGaN is grown.

(16) In a nitrogen atmosphere, annealing for 20min, the growth process is over.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (8)

1. an ultraviolet LED epitaxial structure, is characterized in that, comprises: the substrate, intrinsic AlGaN layer, n-type AlGaN layer, n-doped AlGaN/AlN superlattice layer, quantum well region, superlattice layer stacked sequentially from bottom to top Lattice SL region, p-type AlGaN layer and p++-type BAlGaN layer; The quantum well region and the superlattice SL region are respectively provided with n layers, n≥3, and the quantum well region and the superlattice SL region are alternately stacked; The superlattice SL region includes superlattice SL region-1, superlattice SL region-2, superlattice SL region-3 and superlattice SL region-n; The superlattice SL region-1 includes a 4-6 period superlattice SL region-a; the superlattice SL region-a includes an _{AlyGa1 -yN} layer and an AlInGaN layer located above it, x<y<1; the thickness of the _{AlyGa1 -yN} layer is 2-3nm; the thickness of the AlInGaN layer is 2-3nm; The superlattice SL region-2 includes a superlattice SL region-b of 4-6 periods; the superlattice SL region-b includes a BAlGaN layer and an AlGaN layer above it; the thickness of the BAlGaN layer is 2-3nm; the thickness of the AlGaN layer is 2-3nm; The superlattice SL region-3 includes a 4-6 period superlattice SL region-c; the superlattice SL region-c includes a BInAlGaN layer and an AlInGaN layer above it; the thickness of the BInAlGaN layer is 2-3nm; the thickness of the AlInGaN layer is 2-3nm; The superlattice SL region-n includes a 4-6 period superlattice SL region-d; the superlattice SL region-d includes an AlGaN layer and an AlInGaN layer above it; the thickness of the AlGaN layer is 2-3 nm; the thickness of the AlInGaN layer is 2-3 nm. 2 . The ultraviolet LED epitaxial structure according to claim 1 , wherein the substrate is a sapphire substrate or a silicon substrate. 3 . 3 . The ultraviolet LED epitaxial structure according to claim 1 , further comprising: an AlN layer, and the AlN layer is disposed between the substrate layer and the intrinsic AlGaN layer; 3 . The AlN layer includes a low temperature AlN layer and a high temperature AlN layer; the high temperature AlN layer is located above the low temperature AlN layer; the thickness of the low temperature AlN layer is 10 nm; the thickness of the high temperature AlN layer is 200 nm. 4 . The ultraviolet LED epitaxial structure according to claim 3 , wherein the thickness of the intrinsic AlGaN layer is 100 nm; the thickness of the n-type AlGaN layer is 100-300 nm. 5 . 5 . The ultraviolet LED epitaxial structure according to claim 3 , wherein the thickness of the AlGaN in the n-doped AlGaN/AlN superlattice layer is 2-5 nm, and the thickness of the AlN is 2 nm. 6 . 6. The ultraviolet LED epitaxial structure according to claim 3, wherein the quantum well region comprises quantum well region-1, quantum well region-2, quantum well region-3 and quantum well region-n; The quantum well region-1 includes a quantum well region-a of 3-4 periods; the quantum well region-a includes two layers of AlxGa1 _{- xN} quantum barrier layers and two layers of AlxGa1 _{- x} The InGaN quantum well layer between the N quantum barrier layers, 0<x<1; the thickness of the Al _x Ga _1-x N quantum barrier layer is 12-15 nm; the thickness of the InGaN quantum well layer is 2-3 nm; The quantum well region-2 includes 3-4 periods of quantum well region-b; the quantum well region-b includes two layers of _{AlyGa1 -yN} quantum barrier layers and two layers of AlyGa1 _{- y} The AlInGaN quantum well layer between the N quantum barrier layers, x<y<1; the thickness of the _{AlyGa1 -yN} quantum barrier layer is 12-15nm; the thickness of the AlInGaN quantum well layer is 2-3nm; The quantum well region-3 includes 3-4 periods of quantum well region-c; the quantum well region-c includes two BAlGaN quantum barrier layers and an AlGaN quantum well layer between the two BAlGaN quantum barrier layers; The thickness of the BAlGaN quantum barrier layer is 12-15nm; the thickness of the AlGaN quantum well layer is 2-3nm; The quantum well region-n includes 3-4 periods of quantum well region-d; the quantum well region-d includes two BInAlGaN quantum barrier layers and an AlInGaN quantum well layer located between the two BInAlGaN quantum barrier layers; The thickness of the BInAlGaN quantum barrier layer is 12-15 nm; the thickness of the AlInGaN quantum well layer is 2-3 nm. 7 . The ultraviolet LED epitaxial structure according to claim 6 , wherein the thickness of the p-type AlGaN layer is 500 nm; the thickness of the p++ type BAlGaN layer is 3-5 nm. 8 . 8. the preparation method of a kind of ultraviolet LED epitaxial structure as claimed in claim 7, is characterized in that, concrete method is as follows: (1) A layer of low-temperature AlN layer is grown on the substrate; (2) growing a high temperature AlN layer on the low temperature AlN layer; (3) growing an intrinsic AlGaN layer on the high temperature AlN layer; (4) growing an n-type AlGaN layer on the intrinsic AlGaN layer; (5) growing an n-doped AlGaN/AlN superlattice layer on the n-type AlGaN layer; (6) Growth of a quantum well region-1 on the n-doped AlGaN/AlN superlattice layer (7) growing a layer of superlattice SL region-1 on the quantum well region-1; (8) A layer of quantum well region-2 is grown on the superlattice SL-1; (9) growing a layer of superlattice SL region-2 on the quantum well region-2; (10) A layer of quantum well region-3 is grown on the superlattice SL-2; (11) growing a layer of superlattice SL region-3 on the quantum well region-3; (12) A layer of quantum well region-n is grown on the superlattice SL-3; (13) growing a layer of superlattice SL region-n on the quantum well region-n; (14) growing a p-type AlGaN layer on the superlattice SL-n; (15) A p++-type BAlGaN layer is grown on the p-type AlGaN layer.

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