CN213816182U

CN213816182U - AlGaN-based deep ultraviolet LED epitaxial wafer with Si substrate

Info

Publication number: CN213816182U
Application number: CN202023157209.9U
Authority: CN
Inventors: 高芳亮; 杨金铭
Original assignee: Huizhou Sanhang Uav Technology Research Institute; Shenzhen Angde Global Technology Co ltd
Current assignee: Huizhou Sanhang Uav Technology Research Institute; Shenzhen Angde Global Technology Co ltd
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2021-07-27
Anticipated expiration: 2030-12-24

Abstract

The utility model discloses a AlGaN base deep ultraviolet LED epitaxial wafer of Si substrate, the AlGaN base deep ultraviolet LED epitaxial wafer of Si substrate includes: the high-temperature AlGaN/GaN high-temperature AlGaN/high-temperature AlGaN.

Description

AlGaN-based deep ultraviolet LED epitaxial wafer with Si substrate

Technical Field

The utility model relates to a semiconductor device technical field, in particular to AlGaN base deep ultraviolet LED epitaxial wafer of Si substrate.

Background

The deep ultraviolet light has wide application prospect in the fields of national defense technology, information technology, bio-pharmaceuticals, environmental monitoring, public health, sterilization, disinfection and the like. The traditional ultraviolet light sources used at present are gas lasers and mercury lamps, and have the defects of large volume, high energy consumption, pollution and the like. An AlGaN-based compound semiconductor ultraviolet Light Emitting Diode (LED) is a solid ultraviolet light source and has the advantages of small volume, high efficiency, long service life, environmental friendliness, low energy consumption, no pollution and the like. The AlGaN material with high Al component is an irreplaceable material system for preparing high-performance deep ultraviolet LEDs, has great requirements in civil and military aspects, such as the medical and health fields of sterilization, cancer detection, skin disease treatment and the like, and has the advantages of no mercury pollution, adjustable wavelength, small volume, good integration, low energy consumption, long service life and the like.

In recent years, the development of AlGaN-based deep ultraviolet LEDs has made some progress, but the commercialization of AlGaN-based deep ultraviolet LEDs is still hindered by performance problems such as low external quantum efficiency and low light emitting power, and high-quality epitaxial materials are the basis for preparing high-performance deep ultraviolet LEDs. Currently, high-quality AlGaN materials are generally manufactured by a heteroepitaxy method, a Si substrate is also adopted as an epitaxial substrate of the AlGaN-based deep ultraviolet LED, but a larger lattice mismatch exists between the Si substrate and the epitaxially grown AlGaN material. Therefore, in order to realize the growth of high-quality AlGaN materials and high-performance deep ultraviolet LED epitaxial wafers on Si substrates, it is still necessary to overcome the major defects such as lattice mismatch, crystal dislocation, and stacking fault.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a AlGaN base deep ultraviolet LED epitaxial wafer of Si substrate, aim at solving the problem that the AlGaN base deep ultraviolet LED epitaxial wafer performance remains to improve among the prior art.

The embodiment of the utility model provides a deep ultraviolet LED epitaxial wafer of AlGaN base of Si substrate, it includes: the high-temperature AlGaN/GaN high-temperature AlGaN/high-temperature AlGaN.

Preferably, the thickness of the low-temperature AlN layer is 50-100 nm.

Preferably, the thickness of the high-temperature AlN layer is 200-500 nm.

Preferably, the thickness of the first AlGaN layer is 2-10 nm.

Preferably, the thickness of the second AlGaN layer is 800-2000 nm.

Preferably, the thickness of the n-type doped AlGaN layer is 3-5 μm.

Preferably, the AlGaN multi-quantum well layer is made of Al with 7-10 periods_0.3Ga_0.7N well layer and Al_0.5Ga_0.5N barrier layers.

Preferably, the Al is_0.3Ga_0.7The thickness of the N well layer is 2-3 nm, and the Al is_0.5Ga_0.5The thickness of the N barrier layer is 10-13 nm.

Preferably, from the direction close to the Si substrate to the direction far away from the Si substrate, the content of the Al component in the Al component segmented gradually-changed p-type doped AlGaN layer is gradually reduced from 0.4 to 0, and the thickness of the Al component segmented gradually-changed p-type doped AlGaN layer is 300-350 nm.

Preferably, the thickness of the p-type doped GaN layer is 300-350 nm.

The embodiment of the utility model provides a deep ultraviolet LED epitaxial wafer of AlGaN base of Si substrate, the deep ultraviolet LED epitaxial wafer of AlGaN base of Si substrate includes: the high-temperature AlGaN/GaN high-temperature AlGaN/high-temperature AlGaN. The utility model adopts the technology of combining the low-temperature AlN layer with the high-temperature AlN layer and adopting the amorphous buffer layer to reduce the stress between Si and AlGaN; and the Al component sectional gradient p-type AlGaN structure is adopted, so that the defects of the prior art are overcome, and the high-performance AlGaN-based deep ultraviolet LED is obtained.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without any creative effort.

Fig. 1 is a schematic structural diagram of an AlGaN-based deep ultraviolet LED epitaxial wafer with a Si substrate according to an embodiment of the present invention;

fig. 2 is a schematic flow chart of a method for manufacturing an AlGaN-based deep ultraviolet LED epitaxial wafer with a Si substrate according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in the specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.

The embodiment of the utility model provides a deep ultraviolet LED epitaxial wafer of AlGaN base of Si substrate, as shown in FIG. 1, include: the low-temperature AlGaN/GaN high-temperature AlGaN/.

Because there is great lattice mismatch between Si and AlGaN, the utility model adopts the technology of combining the high-temperature AlN buffer layer at low temperature and the amorphous buffer layer, so as to reduce the stress between Si and AlGaN; and the Al component sectional gradient p-type AlGaN structure is adopted, so that the defects of the prior art are overcome, and the high-performance AlGaN-based deep ultraviolet LED is obtained.

In one embodiment, the low temperature AlN layer 102 has a thickness of 50 to 100nm, such as 75 nm. The low-temperature AlN layer 102 can prevent the Ga and Si from melting back and etching reaction at high temperature, and the low-temperature grown AlN buffer layer (i.e., the low-temperature AlN layer 102) has a higher defect density and can reduce the extension of dislocations into the high-temperature grown AlN buffer layer (i.e., the high-temperature AlN layer 103).

In one embodiment, the high temperature AlN layer 103 has a thickness of 200 to 500nm, such as 350 nm. The low-temperature AlN layer 102 and the high-temperature AlN layer 103 are buffer layers, and provide high-quality templates for the subsequent growth of the first AlGaN layer 104 and the second AlGaN layer 105.

In one embodiment, the first AlGaN layer 104 has a thickness of 2 to 10nm, such as 5 nm. The first AlGaN layer 104 is an amorphous buffer layer AlGaN. The embodiment of the utility model provides an adopt the thin amorphous buffer layer AlGaN of one deck, amorphous material can have a large amount of vacancy defects, and the dislocation is easy to nucleate in this one deck material. Meanwhile, the vacancy defects can promote dislocation to slip in the buffer layer and prevent the dislocation from penetrating to a subsequent epitaxial layer. This large mismatch buffer layer can thus act as a stress relief. The Al composition in the first AlGaN layer 104 is 0.7 (the composition means the ratio of Al to the total content of Al and Ga), that is, the first AlGaN layer 104 is Al_0.7Ga_0.3And N layers.

In one embodiment, the thickness of the second AlGaN layer 105 is 800-2000 nm, such as 1500 nm. The Al composition in the second AlGaN layer 105 is 0.5, that is, the second AlGaN layer 105 is Al_0.5Ga_0.5And N layers. The first AlGaN layer 104 and the second AlGaN layer 105 can provide a high quality material template for the subsequent growth of the n-type doped AlGaN layer 106.

In one embodiment, the thickness of the n-doped AlGaN layer 106 is 3 to 5 μm, such as 4 μm, and the n-doped AlGaN layer 106 functions to provide electrons to the MQW layer.

In one embodiment, the AlGaN MQW layer 107 is made of 7-10 periods of Al_0.3Ga_0.7N well layer and Al_0.5Ga_0.5N barrier layers (e.g., 8 cycles). The above-mentionedThe AlGaN multi-quantum well layer 107 is an active light emitting layer of the LED, and electrons and holes are radiatively recombined in the layer to emit light of a specific wavelength. In which one period is formed by one layer of Al_0.3Ga_0.7N well layer and one layer of Al_0.5Ga_0.5A N barrier layer, such as a layer of Al_0.3Ga_0.7N well layer and one layer of Al_0.5Ga_0.5N barrier layers are repeatedly and alternately laminated to form Al with multiple periods_0.3Ga_0.7N well layer and Al_0.5Ga_0.5And N barrier layers.

In one embodiment, the Al_0.3Ga_0.7The thickness of the N well layer is 2-3 nm, such as 2.5nm, and the Al_0.5Ga_0.5The thickness of the N barrier layer is 10-13 nm, such as 12 nm.

The electron blocking layer 108 can prevent electrons from overflowing during current injection, and the electrons cannot be completely confined in the quantum well for radiative recombination. The electron blocking layer 108 may be Al_0.4Ga_0.6An N electron blocking layer. The thickness of the electron blocking layer 108 is 20 to 50nm, such as 30 nm.

In an embodiment, the content of the Al component in the Al component segmentally graded p-type doped AlGaN layer 109 is gradually reduced from 0.4 to 0 (i.e., from Al) from the direction close to the Si substrate to the direction away from the Si substrate_0.4Ga_0.6Reduction of N to Al₀Ga₁N), the thickness of the Al component segmented gradient p-type doped AlGaN layer 109 is 300-350 nm, such as 325 nm. The Al component graded p-type doped AlGaN layer 109 provides holes for the multiple quantum well active layer. In the deep ultraviolet LED device structure, electrons are injected into the multiple quantum well region from the n-type layer and are recombined with holes injected from the p-type region, so that the electron current density along the growth direction of the material is gradually reduced, and the extra current generated by the overflow of the electron current to the p-type layer is defined as electron leakage current. Due to the fact that energy bands are bent due to polarized electric fields in the multiple quantum wells and the electron blocking layers, the quantum barriers and the traditional electron blocking layers cannot effectively block electrons in the quantum wells, and therefore the deep ultraviolet LED with the traditional structure has obvious electron leakage. The electrons injected from the Al composition graded p-type doped AlGaN layer 109 are more effectively confined in the multiple quantum well and have a higher electron mobilityMany holes are effectively injected into the active region, so that the radiation recombination efficiency of the deep ultraviolet LED with the Al component segmented gradual change p-type doped AlGaN layer 109 is effectively improved.

The p-type doped GaN layer 110 can provide holes for the mqw layer, and is also beneficial to forming good ohmic contact with the metal electrode. The thickness of the p-type doped GaN layer 110 is 300-350 nm, such as 325 nm. In the p-type doped GaN layer 110, the doping element is Mg, and the doping concentration of Mg is 1 × 10¹⁷～5×10¹⁸。

The embodiment of the utility model provides a preparation method of AlGaN base deep ultraviolet LED epitaxial wafer as above, as shown in FIG. 2, it includes step S201 ~ S210:

s201, selecting a Si substrate;

s202, growing a low-temperature AlN layer on the Si substrate;

s203, growing a high-temperature AlN layer on the low-temperature AlN layer;

s204, growing a first AlGaN layer on the high-temperature AlN layer;

s205, growing a second AlGaN layer on the first AlGaN layer;

s206, growing an n-type doped AlGaN layer on the second AlGaN layer;

s207, growing an AlGaN multi-quantum well layer on the n-type doped AlGaN layer;

s208, growing an electronic barrier layer on the AlGaN multi-quantum well layer;

s209, growing an Al component sectional gradient p-type doped AlGaN layer on the electron barrier layer;

s210, growing a p-type doped GaN layer on the Al component sectional gradient p-type doped AlGaN layer

In step S201, a commercially available and common Si substrate may be selected.

In the step S202, in the step of growing the low-temperature AlN layer, a metal organic chemical vapor deposition method is used to grow the low-temperature AlN layer, and the process conditions are as follows: trimethylaluminum is used as an Al source, ammonia gas is used as an N source, hydrogen is used as a carrier gas, the pressure of a reaction chamber is 50-300 torr, the temperature of a substrate is 900-1000 ℃, the beam current ratio V/III is 3000-5000, and the growth rate is 1-2 mu m/h.

In the step S203, in the high-temperature AlN layer growing step, a metal organic chemical vapor deposition method is used to grow a high-temperature AlN layer on the low-temperature AlN layer, and the process conditions are as follows: trimethylaluminum is used as an Al source, ammonia gas is used as an N source, hydrogen is used as a carrier gas, the pressure of a reaction chamber is 50-300 torr, the temperature of a substrate is 1000-1260 ℃, the beam current ratio V/III is 3000-5000, and the growth rate is 1-2 mu m/h.

In step S204, in the first AlGaN layer growing step, a metal organic chemical vapor deposition method is used to grow a first AlGaN layer on the high temperature AlN layer, and the process conditions are as follows: trimethylaluminum is used as an Al source, trimethylgallium is used as a Ga source, ammonia is used as an N source, hydrogen is used as a carrier gas, the pressure of a reaction chamber is 50-300 torr, the temperature of a substrate is 600-900 ℃, the beam current ratio V/III is 3000-5000, and the growth rate is 1-2 μm/h.

In step S205, in the second AlGaN layer growth step, a second AlGaN layer is grown on the first AlGaN layer by using a metal organic chemical vapor deposition method, and the process conditions are as follows: trimethylaluminum is used as an Al source, trimethylgallium is used as a Ga source, ammonia is used as an N source, the pressure of a reaction chamber is 50-300 torr, the temperature of a substrate is 1000-1260 ℃, the beam current ratio V/III is 3000-5000, and the growth rate is 1-2 mu m/h.

In step S206, in the step of epitaxially growing the n-type doped AlGaN layer, a metal organic chemical vapor deposition method is used to grow the n-type doped AlGaN layer on the second AlGaN layer, and the process conditions are as follows: trimethylaluminum is used as an Al source, trimethylgallium is used as a Ga source, ammonia is used as an N source, the pressure of a reaction chamber is 50-300 torr, the temperature of a substrate is 1000-1260 ℃, the beam current ratio V/III is 3000-5000, and the growth rate is 2-4 mu m/h; the n-type doped AlGaN layer is doped with Si with the doping concentration of 1 multiplied by 10¹⁷～1×10²⁰cm^-3。

In the step S207, in the step of epitaxial growth of the AlGaN multi-quantum well layer, 7 to 10 periods of Al are grown on the n-type doped AlGaN layer by using a metal organic chemical vapor deposition method_0.3Ga_0.7N well layer/Al_0.5Ga_0.5N base layers, the process conditions are as follows: trimethylaluminum as Al source and trimethylgallium as Ga source, ammonia gas as N source, reaction chamber pressure of 50-300 torr, substrate temperature of 1000-1260 ℃, beam current ratio V/III of 3000-5000, and growth rate of 2-4 μm/h.

In the step S208, in the step of epitaxial growth of the electron blocking layer, Al is grown on the AlGaN multi-quantum well layer by using a metal organic chemical vapor deposition method_0.4Ga_0.6The process conditions of the N electron blocking layer are as follows: trimethylaluminum is used as an Al source, trimethylgallium is used as a Ga source, ammonia is used as an N source, the pressure of a reaction chamber is 50-300 torr, the temperature of a substrate is 1000-1260 ℃, the beam current ratio V/III is 3000-5000, and the growth rate is 2-4 mu m/h.

In step S209, in the step of epitaxial growth of the p-type doped AlGaN layer with a graded Al composition, a metal organic chemical vapor deposition method is used to grow the p-type doped AlGaN layer with a graded Al composition on the electron blocking layer, and the process conditions are as follows: trimethylaluminum is used as an Al source, trimethylgallium is used as a Ga source, ammonia is used as an N source, the pressure of a reaction chamber is 50-300 torr, the temperature of a Si substrate is 1000-1260 ℃, the beam current ratio V/III is 3000-5000, and the growth rate is 2-4 mu m/h.

In step S210, in the step of epitaxial growth of the p-type doped GaN layer, a metal organic chemical vapor deposition method is used to grow the p-type doped GaN layer on the Al component graded p-type doped AlGaN layer, and the process conditions are as follows: trimethyl gallium is used as a Ga source, ammonia gas is used as an N source, the pressure of a reaction chamber is 50-300 torr, the temperature of a Si substrate is 1000-1060 ℃, the beam current ratio V/III is 3000-5000, and the growth rate is 2-4 mu m/h.

The AlGaN-based deep ultraviolet LED grown on the Si substrate and prepared by one embodiment of the utility model is manufactured into a chip: the electron beam evaporation electrode on the AlGaN-based deep ultraviolet LED epitaxial wafer grown on the Si substrate prepared in this example was annealed to form an ohmic contact. Under the working current of 50mA, the AlGaN-based deep ultraviolet LED device prepared on the Si substrate has the light output power of 3.3mW and the starting voltage value of 5.18V. The AlGaN-based deep ultraviolet LED grown on the Si substrate and prepared by the other embodiment of the utility model is manufactured into a chip: the electron beam evaporation electrode on the AlGaN-based deep ultraviolet LED epitaxial wafer grown on the Si substrate prepared in this example was annealed to form an ohmic contact. Under the working current of 50mA, the light output power of the AlGaN-based deep ultraviolet LED device prepared on the Si substrate is 3.5mW, and the starting voltage value is 5.5V.

The embodiment of the utility model adopts the technology of combining the high-temperature AlN buffer layer at low temperature and the amorphous buffer layer, thereby reducing the lattice mismatch between Si and AlGaN; the defect density in the film is relieved, so that the growth of the AlGaN film with high crystal quality and the AlGaN-based deep ultraviolet LED epitaxial wafer is realized; in the preparation method of the utility model, the sectional gradual change p-type AlGaN structure of Al component is adopted, which is beneficial to overcoming the problem of low light-emitting efficiency of the AlGaN-based deep ultraviolet LED caused by polarization effect and obtaining the high-performance AlGaN-based deep ultraviolet LED; the utility model uses Si as the substrate, the substrate is easy to obtain and has low price, which is beneficial to reducing the production cost; the growth process of the utility model is unique, simple and feasible, and has repeatability; the utility model discloses can obtain high quality and the smooth epitaxial layer film in interface, and then prepare high performance, the AlGaN base photoelectric device that luminous efficiency is high, this method is simple and easy, the effect is showing, the low price.

The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, the present invention can be further modified and modified, and such modifications and modifications also fall within the protection scope of the appended claims.

It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Claims

1. An AlGaN-based deep ultraviolet LED epitaxial wafer with a Si substrate is characterized by comprising: the high-temperature AlGaN/GaN high-temperature AlGaN/high-temperature AlGaN.

2. The AlGaN-based deep ultraviolet LED epitaxial wafer according to claim 1, wherein the low-temperature AlN layer has a thickness of 50 to 100 nm.

3. The AlGaN-based deep ultraviolet LED epitaxial wafer according to claim 1, wherein the high-temperature AlN layer has a thickness of 200 to 500 nm.

4. The AlGaN-based deep ultraviolet LED epitaxial wafer according to claim 1, wherein a thickness of the first AlGaN layer is 2 to 10 nm.

5. The AlGaN-based deep ultraviolet LED epitaxial wafer according to claim 1, wherein the thickness of the second AlGaN layer is 800-2000 nm.

6. The AlGaN-based deep ultraviolet LED epitaxial wafer of claim 1, wherein the thickness of the n-type doped AlGaN layer is 3-5 μm.

7. The AlGaN-based deep ultraviolet LED epitaxial wafer of claim 1, wherein the AlGaN multi-quantum well layer consists of 7-10 periods of Al_0.3Ga_0.7N well layer and Al_0.5Ga_0.5N barrier layers.

8. The AlGaN-based deep ultraviolet LED epitaxial wafer of claim 7, wherein the Al is_0.3Ga_0.7The thickness of the N well layer is 2-3 nm, and the Al is_0.5Ga_0.5The thickness of the N barrier layer is 10-13 nm.

9. The AlGaN-based deep ultraviolet LED epitaxial wafer according to claim 1, wherein the content of Al component in the Al component segmented and gradually-changed p-type doped AlGaN layer is gradually reduced from 0.4 to 0 in the direction from the Si substrate to the Si substrate, and the thickness of the Al component segmented and gradually-changed p-type doped AlGaN layer is 300-350 nm.

10. The AlGaN-based deep ultraviolet LED epitaxial wafer according to claim 1, wherein the thickness of the p-type doped GaN layer is 300-350 nm.