阅读说明：本技术 一种近似同质外延hemt器件结构及其制备方法 (Approximate homoepitaxy HEMT device structure and preparation method thereof ) 是由 吴勇 汪琼 王东 陈兴 严伟伟 陆俊 葛林男 何滇 曾文秀 王俊杰 穆潘潘 操 于 2020-05-28 设计创作，主要内容包括：本发明公开了一种近似同质外延HEMT器件结构,属于微电子技术领域,包括从下至上依次排布的衬底、低温成核层、石墨烯层一、缓冲层一、恢复层、石墨烯层二、缓冲层二、高阻层、沟道层以及势垒层,本发明可以大幅度降低材料的位错密度,提高晶格质量,从而提升HEMT器件的电子迁移率、击穿电压以及漏电流等特性,适用于高压大功率电子器件应用,通过插入石墨烯层易于剥离,可以有效的缓解蓝宝石于氮化镓层的热失配以及可以提高蓝宝石衬底和氮化镓薄膜衬底的利用率,有效降低成本。(The invention discloses an approximate homoepitaxy HEMT device structure, which belongs to the technical field of microelectronics, and comprises a substrate, a low-temperature nucleating layer, a first graphene layer, a first buffer layer, a recovery layer, a second graphene layer, a second buffer layer, a high-resistance layer, a channel layer and a barrier layer which are sequentially arranged from bottom to top.)

1. The near homoepitaxy HEMT device structure is characterized by comprising a substrate (L1), a low-temperature nucleation layer (L2), a first graphene layer (L3), a first buffer layer (L4), a recovery layer (L5), a second graphene layer (L6), a second buffer layer (L7), a high-resistance layer (L8), a channel layer (L9) and a barrier layer (L10) which are sequentially arranged from bottom to top.

2. The near homoepitaxial HEMT device structure of claim 1, wherein said substrate (L1) is 2-8inch in size and is made of sapphire.

3. The structure of the near homoepitaxial HEMT device in claim 1, wherein the low temperature nucleation layer (L2) is any one or combination of ALN, ALGaN and GaN, the growth temperature is 400 ℃ and 700 ℃, and the film thickness is 10-50 nm.

4. The near homoepitaxial HEMT device structure of claim 1, wherein each of said graphene layer one (L3) and graphene layer two (L6) has a film thickness of 0.3nm to 2 nm.

5. The near homoepitaxy HEMT device structure of claim 1, wherein the first buffer layer (L4) and the second buffer layer (L7) are both unintentionally doped gallium nitride layers deposited by metal organic vapor phase epitaxy, the growth temperature is 900-1120 ℃, and the film thickness is 0.5-2 μm.

6. The near homoepitaxial HEMT device structure of claim 1, wherein said recovery layer (L5) is a high quality gallium nitride thin film layer formed by unintentional dopant growth using metal organic vapor phase epitaxial deposition, the thickness of the thin film is in the range of 5um-50um, and the growth temperature is 1120-1150 ℃.

7. The nearly homoepitaxial HEMT device structure of claim 1, wherein said high resistance layer (L8) is a semi-insulating high quality gallium nitride thin film layer formed by unintentional dopant growth using metal organic vapor phase epitaxy deposition, with a film thickness in the range of 1um-5 um.

8. The near homoepitaxial HEMT device structure of claim 1, wherein said channel layer (L9) is a semi-insulating high quality gallium nitride channel thin film layer formed by metal organic vapor phase epitaxial deposition unintentional dopant growth, with a film thickness in the range of 50-200 nm.

9. The near homoepitaxial HEMT device structure of claim 1, wherein said barrier layer (L10) has the formula Al_xGa_1-xN, wherein 0<x<1, the thickness is 5-35 nm.

Technical Field

The invention belongs to the technical field of microelectronics, and relates to epitaxial preparation of a semiconductor device, in particular to a similar homoepitaxy HEMT device structure and a preparation method thereof.

Background

The third generation Semiconductor material, i.e. the Wide Band Gap Semiconductor (WBGS) Semiconductor material, is developed following the first generation silicon, germanium, the second generation gallium arsenide, indium phosphide, etc. Among the third generation semiconductor materials, gallium nitride (GaN) has superior properties such as wide band gap, direct band gap, high breakdown electric field, lower dielectric constant, high electron saturation drift velocity, strong radiation resistance, and good chemical stability, and becomes a key semiconductor material for manufacturing a new generation of microelectronic devices and circuits following germanium, silicon, and gallium arsenide. Particularly, the high-temperature, high-power, high-frequency and anti-radiation electronic device and the full-wavelength and short-wavelength photoelectric device have the unique advantages, are ideal materials for realizing the high-temperature, high-power, high-frequency, anti-radiation and full-wavelength photoelectric devices, and are key basic materials for the continuous development of high and new technologies such as microelectronics, power electronics, photoelectrons and the like, and the national defense industry, the information industry, the electromechanical industry, the energy industry and other strut industries after entering the 21 st century.

However, because of the large lattice mismatch between the gallium nitride HEMT device and the heterogeneous substrate, even if the nucleation layer and the AlGaN or GaN buffer layer play a role in buffering between the substrate and the GaN layer, the crystal quality of the GaN layer finally grown is not good enough, and the quality of the HEMT is affected, so that the breakdown voltage of the device is reduced, and the electron mobility is reduced, so that the performance of the current gallium nitride HEMT device is far lower than the theoretical limit.

Disclosure of Invention

The invention aims to solve the problem of poor lattice quality of the existing gallium nitride HEMT device, and provides an HEMT epitaxial structure and a preparation method thereof, which can improve the quality of the HEMT device.

An approximate homoepitaxy HEMT device structure comprises a substrate, a low-temperature nucleation layer, a first graphene layer, a first buffer layer, a recovery layer, a second graphene layer, a second buffer layer, a high-resistance layer, a channel layer and a barrier layer which are sequentially arranged from bottom to top.

Preferably, the size of the substrate is 2-8inch, and the material is sapphire.

Preferably, the low-temperature nucleation layer is any one or combination of ALN, ALGaN and GaN, the growth temperature is 400-700 ℃, and the film thickness is 10-50 nm.

Preferably, the film thickness of the first graphene layer and the film thickness of the second graphene layer are both 0.3nm-2 nm. The graphene and the silicon nitride are convenient to strip, and the graphene has high conductivity and cannot have other influences when stored in an epitaxial layer.

Preferably, the first buffer layer and the second buffer layer are both unintentionally doped gallium nitride layers deposited by metal organic vapor phase epitaxy, the growth temperature is 900-1120 ℃, and the film thickness is 0.5-2 um.

Preferably, the recovery layer is a high-quality gallium nitride thin film layer formed by adopting metal organic vapor phase epitaxial deposition and unintentional doping growth, the thickness of the high-quality gallium nitride thin film layer is larger than that of the normal gallium nitride thin film layer, the thickness range of the high-quality gallium nitride thin film layer is 5-50 um, and the growth temperature of the high-quality gallium nitride thin film layer is 1120-1150 ℃.

Preferably, the high-resistance layer is a semi-insulating high-quality gallium nitride thin film layer formed by adopting metal organic vapor phase epitaxial deposition and unintentional doping growth, and the thickness range of the thin film is 1-5 um.

Preferably, the channel layer adopts a semi-insulating high-quality gallium nitride channel thin film layer formed by metal organic vapor phase epitaxial deposition and unintentional doping growth, and the thickness range of the thin film is 50-200 nm.

Preferably, the barrier layer is specifically an aluminum gallium nitrogen barrier layer, and the structural formula of the barrier layer is Al_xGa_1-xN, wherein 0<x<1, the thickness is 5-35 nm.

According to the preparation method, the epitaxial layer can be selectively grown to the recovery layer and then moved out of the cavity, the graphene layer I is stripped, the stripped buffer layer and the recovery layer are pure gallium nitride films which are continuously used as substrates and placed back to the cavity to grow the subsequent layer, and the HEMT structure grows integrally in a homoepitaxial mode. The sapphire substrate after being stripped can be reused.

Furthermore, the preparation method of the invention can also choose to finish the growth of the whole epitaxial layer at one time, but the regrowth after stripping is better for reducing the defects. After the epitaxial layer is grown, the graphene can be selected to be continuously stripped at the second position according to the chip process requirements, and the complete HEMT structure is stripped. The stripped gallium nitride film substrate can be repeatedly used

Compared with the prior art, the structure and the preparation method thereof have the following advantages: the dislocation density of the material can be greatly reduced, the lattice quality is improved, the characteristics of electron mobility, breakdown voltage, leakage current and the like of the HEMT device are improved, the HEMT device is suitable for high-voltage high-power electronic devices, the graphene layer is easily stripped by inserting, the thermal mismatch of sapphire on a gallium nitride layer can be effectively relieved, the utilization rate of the sapphire substrate and the gallium nitride film substrate can be improved, and the cost is effectively reduced.

Drawings

Fig. 1 is a schematic structural diagram of an HEMT epitaxial structure according to an embodiment of the present invention;

fig. 2 is a diagram showing the X-ray diffraction test result of the epitaxial layer of the gallium nitride device prepared by the method of the present invention.

Wherein: the device comprises a substrate L1, a low-temperature nucleation layer L2, a graphene layer I L3, a buffer layer I4, a restoration layer L5, a graphene layer II L6, a buffer layer II L7, a high-resistance layer L8, a channel layer L9 and a barrier layer L10.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

The invention relates to an approximate homoepitaxy HEMT device structure, which comprises a substrate L1, a low-temperature nucleation layer L2, a first graphene layer L3, a first buffer layer L4, a recovery layer L5, a second graphene layer L6, a second buffer layer L7, a high-resistance layer L8, a channel layer L9 and a barrier layer L10 which are sequentially arranged from bottom to top, and is specifically prepared by adopting the following method: