CN112687768B

CN112687768B - Epitaxial material growth method capable of modulating grating array structure

Info

Publication number: CN112687768B
Application number: CN202011389027.6A
Authority: CN
Inventors: 南琦
Original assignee: Musheng Semiconductor Technology Suzhou Co ltd
Current assignee: Musheng Semiconductor Technology Suzhou Co ltd
Priority date: 2020-12-01
Filing date: 2020-12-01
Publication date: 2021-11-05
Anticipated expiration: 2040-12-01
Also published as: CN112687768A

Abstract

The invention relates to an epitaxial material growth method capable of modulating a grating array structure, which comprises the following steps: growing an AlN layer on the diamond substrate; growing an n-type AlGaN layer on the AlN layer; growing an AlGaN well layer, an AlGaN/AlN transition layer, a C-based diamond layer and an AlN quantum barrier layer on the n-type AlGaN layer in sequence, and repeatedly growing a plurality of groups of AlGaN well layers, AlGaN/AlN transition layers and C-based diamond layers to form a multi-quantum well layer; and growing a P-type AlGaN layer on the multi-quantum well layer. The epitaxial material growth method capable of modulating the grating array structure can directly adjust the C-based diamond polarization grating filter structure in the epitaxial structure to achieve the required polarized light source, does not need to additionally coat a film modulation structure outside, and avoids the loss of excessive light power.

Description

Epitaxial material growth method capable of modulating grating array structure

Technical Field

The invention relates to the field of epitaxial material growth methods, in particular to an epitaxial material growth method capable of modulating a grating array structure.

Background

The traditional growth technology and performance characterization technology of GaN, AlGaN and AlN materials have greatly improved, and particularly the preparation technology by using the MOCVD method has been developed into a commercial technology. In contrast, the material growth of the ALGaN ternary compound and the AlInGaN quaternary compound and the preparation technology of the ultraviolet LED device are still immature, and many basic physicochemical problems are not reasonably and scientifically explained. Due to the lack of intrinsic substrate materials, group III nitride semiconductor materials also primarily employ methods of heteroepitaxial growth on sapphire substrates. Because of the large lattice mismatch and thermal mismatch between the sapphire substrate and the group III nitride material, a large defect density is introduced into the material, which has a serious negative effect on the crystal quality and the optoelectronic characteristics of the epitaxial layer, and finally the reliability and the service life of the device are damaged.

According to the quality test analysis of the AlGaN film, the HT-AlN buffer layer with proper thickness can effectively improve the crystal quality of the AlGaN film. The AlN buffer layer can be used as a transition layer or a modulation layer to reduce lattice mismatch between the sapphire substrate and the AlGaN film, so that tensile stress in the AlGaN film is properly released, and the high-quality crack-free AlGaN epitaxial film is favorably obtained.

At the present stage, a low-temperature growth mode is adopted for half of the bottom buffer layer so as to reduce defect density and stress mismatch in the crystal material as much as possible. However, the AlGaN material has high growth temperature and high pressure, and is difficult to grow into a large-area high-quality bulk material under a balanced condition; in the non-equilibrium growth process, Al atoms have large viscosity coefficient and strong pre-reaction, and are difficult to effectively control two-dimensional growth, so that the defects of the film have high density, the surface is uneven, the polarity is mixed, the mismatch stress cannot be effectively released, and the like.

In addition, after the epitaxial material is grown, in order to obtain modulated linearly polarized light, the photoelectric device can be realized only by adopting a chip manufacturing process, and mainly in the manufacturing process of the device, a layer of DBR or OBR film is coated on the surface of the device material to filter out specific polarized light. Since it is inevitable to filter the light source, excessive optical power loss is incurred, all being shielded by the screen.

Disclosure of Invention

The invention aims to provide an epitaxial material growth method capable of modulating a grating array structure, which is used for solving the problem of excessive optical power loss caused by modulating linearly polarized light by adopting a chip process in the prior art.

The invention provides an epitaxial material growth method capable of modulating a grating array structure, which comprises the following steps:

(1) growing an AlN layer on the diamond substrate;

(2) growing an n-type AlGaN layer on the AlN layer;

(3) sequentially growing an AlGaN well layer, an AlGaN/AlN transition layer, a C-based diamond layer and an AlN quantum barrier layer on the n-type AlGaN layer, and repeatedly growing a plurality of groups of AlGaN well layers, AlGaN/AlN transition layers, C-based diamond layers and AlN quantum barrier layers to form a multi-quantum well layer;

(4) and growing a P-type AlGaN layer on the multi-quantum well layer.

Further, the growth temperature of the AlGaN well layer is 1000-1300 ℃.

Further, the thickness of the AlGaN/AlN transition layer is 100-300 nm.

Further, the growth of the C-based diamond layer is specifically: and (3) introducing a C source at 1300-1500 ℃, and producing the diamond compact layer film by adopting a high-temperature CVD reaction, wherein the C source is CH4/H2 gas.

Furthermore, the growth temperature of the C-based diamond layer is 100-500 ℃ higher than that of the AlGaN well layer.

Furthermore, the C-based diamond layer is doped with a certain component of Si element to modulate the conductive property of the diamond layer.

Further, the C-based diamond layer is a polarization grating array.

Further, the AlN layer is of a nano-pillar array structure.

The technical scheme of the invention has the beneficial effects that:

the epitaxial material growth method capable of modulating the grating array structure can directly adjust the C-based diamond polarization grating filter structure in the epitaxial structure to achieve the required polarized light source, does not need to additionally coat a film modulation structure outside, and avoids the loss of excessive light power.

Drawings

FIG. 1 is a flow chart of a method for growing an epitaxial material that can modulate a grating array structure according to the present invention;

fig. 2 is a schematic TEM view of an epitaxial material prepared by the method of the present invention.

FIG. 3 is a schematic view of the structure of the C-based diamond layer according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.

As shown in fig. 1, the present invention provides a method for growing an epitaxial material capable of modulating a grating array structure, comprising the following steps:

(1) growing an AlN layer on the diamond substrate, wherein the AlN layer is of a nano-pillar array structure;

(2) growing an n-type AlGaN layer on the AlN layer;

(4) and growing a P-type AlGaN layer on the multi-quantum well layer.

In the embodiment, the lattice constant of the diamond substrate is almost free from lattice mismatch compared with an AlGaN/AlN material, the AlGaN/AlN crystal material prepared on the diamond substrate is also prepared at high temperature (1400 ℃, defect impurities can be well removed from the bottom layer section, the growth temperature and the annealing temperature can be controlled at 1200-1700 ℃ at the high temperature section, the AlGaN/AlN crystal material is more suitable for the growth of a high-quality AlGaN/AlN material system, and the grown V-pits are expanded and have smaller sizes as shown in figure 2.

Specifically, the growth temperature of the AlGaN well layer is 1000-: introducing a C source at 1300 plus 1500 ℃, producing the diamond compact layer film by adopting a high-temperature CVD reaction, wherein the C source is CH4/H2 gas, can be synthesized and grown into a diamond structure in the temperature range, simultaneously has the properties of a semiconductor and a grating filter, can effectively filter TM polarized light, has the function of filtering the TM polarized light by a grating array, and designs the growth by designing a function relationship of gradually increasing or decreasing the layer thickness according to the requirements of grating filtration by the thickness of multiple layers of C-based diamond layers.

The growth temperature of the C-based diamond layer is 100-500 ℃ higher than that of the AlGaN well layer, and the grown grating array modulation structure grows at high temperature, and is subjected to high-temperature annealing embrittlement for periodic change of the epitaxial structure along with the modulation period change of the thickness and phase change, so that the crystal quality of the original structure is further improved, and the quality advantage and the functional advantage brought by the crystal quality are obvious.

The C-based diamond layer is doped with Si element with certain components to modulate the conductive property of the diamond layer.

In summary, the epitaxial material growth method for the modulatable grating array structure of the present invention can directly adjust the C-based diamond polarization grating filter structure in the epitaxial structure to achieve the required polarized light source without an additional coating thin film modulation structure outside, thereby avoiding the loss of excessive optical power.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for growing an epitaxial material capable of modulating a grating array structure is characterized by comprising the following steps:

(1) growing an AlN layer on the diamond substrate;

(2) growing an n-type AlGaN layer on the AlN layer;

(4) growing a P-type AlGaN layer on the multi-quantum well layer; the C-based diamond layer is a polarization grating array.

2. The method as claimed in claim 1, wherein the AlGaN well layer is grown at a temperature of 1000-1300 ℃.

3. The method as claimed in claim 1, wherein the AlGaN/AlN transition layer has a thickness of 100-300 nm.

4. The method for growing an epitaxial material of a modulatable grating array structure according to claim 1, wherein the growth of the C-based diamond layer is specifically as follows: and (3) introducing a C source at 1300-1500 ℃, and producing the diamond compact layer film by adopting a high-temperature CVD reaction, wherein the C source is CH4/H2 gas.

5. The method as claimed in claim 1, wherein the growth temperature of the C-based diamond layer is 100-500 ℃ higher than that of the AlGaN well layer.

6. The method of claim 1, wherein the C-based diamond layer is doped with a Si element to modulate the conductivity of the diamond layer.

7. The method of claim 1, wherein the AlN layer is in a nano-pillar array structure.