阅读说明：本技术 一种增强型hemt器件结构及其制备方法 (Enhanced HEMT device structure and preparation method thereof ) 是由 王东 汪琼 吴勇 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：本发明公开了一种增强型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、缓冲层、高阻层、沟道层、势垒层、插入层以及P-型层,势垒层采用特定条件下生长的ALInN层,可以获得表面较为平坦的ALInN势垒层,从而获得较高的有效表面载流子浓度,插入层为MgN层,既可以有效抓捕ALInN层中的部分缺陷,也可以提高Mg的掺杂,采用特定的生长环境生长P-型层,提高空穴浓度的同时实现稳定的阈值电压,较高的可靠性,从而提高了HEMT器件的工作效率。(The invention discloses an enhanced HEMT device structure, which belongs to the technical field of microelectronics, and comprises a substrate, a low-temperature nucleating layer, a buffer layer, a high-resistance layer, a channel layer, a barrier layer, an insertion layer and a P-type layer which are sequentially arranged from bottom to top, wherein the barrier layer adopts an ALInN layer grown under specific conditions, and can obtain an ALInN barrier layer with a relatively flat surface, so that a relatively high effective surface carrier concentration is obtained, the insertion layer is an MgN layer, so that partial defects in the ALInN layer can be effectively caught, Mg doping can also be improved, the P-type layer is grown in a specific growth environment, the hole concentration is improved, and meanwhile, a stable threshold voltage and relatively high reliability are realized, so that the working efficiency of an HEMT device is improved.)

1. An enhancement type HEMT device structure is characterized by comprising a substrate (L1), a low-temperature nucleation layer (L2), a buffer layer (L3), a high-resistance layer (L4), a channel layer (L5), a barrier layer (L6), an insertion layer (L7) and a P-type layer (L8) which are sequentially arranged from bottom to top.

2. An enhancement mode HEMT device structure according to claim 1, wherein said substrate (L1) is 2-8inch in size and is made of any one of silicon, silicon carbide, gallium nitride and diamond.

3. The enhancement type HEMT device structure according to claim 1, wherein the channel layer (L5) is grown by introducing triethyl gallium through metal organic vapor phase epitaxy deposition, the thickness of the channel layer (L5) is 50-200nm, and the growth speed is 0.5-1.5 um/h.

4. An enhancement mode HEMT device structure according to claim 1, wherein said barrier layer (L6) is in particular an ALInN barrier layer grown by metal organic vapor phase epitaxial deposition at a temperature of 700-900 ° and a pressure of 40-100 torr with a thickness of 5-35 nm.

5. An enhancement HEMT device structure according to claim 1, wherein an insertion layer (L7) of MgN is inserted after the end of the barrier layer (L6).

6. An enhancement mode HEMT device structure according to claim 1, wherein said P-type layer (L8) is a Mg-InGaN layer grown by metal-organic vapor phase epitaxial deposition.

7. An enhancement mode HEMT device structure according to claim 5, characterized in that the thickness of said insertion layer (L7) is between 2nm and 10 nm.

8. An enhancement mode HEMT device structure according to claim 6, wherein the thickness of said P-type layer (L8) is 50-200 nm.

Technical Field

The invention belongs to the technical field of microelectronics, and relates to epitaxial preparation of a semiconductor device, an enhanced 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.

For the ALInN material with high AL composition, the density of the surface charge introduced by spontaneous polarization difference is larger than that of a typical ALGaN/GaN heterojunction, and the ALInN material is widely applied to high-speed electronic devices, but the ALInN material is difficult to epitaxially grow, and the electrical characteristics of the ALInN/GaN material are seriously influenced by stroke phase separation, V-shaped defects, point defects and the like in the growth process. In addition, in order to realize the enhancement type HEMT device, a p-type gate process is usually adopted, and in order to regulate and control the two-dimensional electron gas by the enhancement gate, the distance between the p-type gate and the two-dimensional electron gas needs to be reduced, so that when the p-type gate is grown, the growth of a p-type layer needs to be immediately realized. However, researches find that when a p-type material is grown by a conventional MOCVD process, due to the memory effect of Mg, the incorporation of Mg doping needs a long time, so that very high Mg doping cannot be immediately realized, and the grown material has a weak p-type or unintended doping type, so that the growth of a p-type layer cannot be immediately realized.

Disclosure of Invention

The invention aims to overcome the problems and provides a HEMT epitaxial structure and a preparation method thereof, which can improve the lattice quality, obtain higher Mg doping and realize effective activation to generate high-concentration holes.

An enhancement type HEMT device structure comprises a substrate, a low-temperature nucleating layer, a buffer layer, a high-resistance layer, a channel layer, a barrier layer, an insertion layer and a P-type layer which are sequentially arranged from bottom to top.

Preferably, the substrate is any material that can be used to epitaxially grow a gallium nitride film, including insulating or semi-insulating sapphire, silicon carbide, gallium nitride, and diamond, with dimensions in the range of 2-8 inches.

Preferably, the channel layer is formed by introducing triethyl gallium through metal organic vapor phase epitaxy deposition and growing at a low growth rate, so that the channel layer with better lattice quality can be ensured to grow. The thickness range of the channel layer is 50-200nm, and the length speed is 0.5-1.5 um/h.

Preferably, the barrier layer is an ALInN layer grown at a specific temperature and a low pressure by adopting metal organic chemical vapor deposition, the thickness is 10-35nm, the temperature is 700-900 ℃, the pressure is 40-100 torr, and the ALInN layer with a relatively flat surface can be obtained under the growth condition.

Preferably, the insertion layer is an MgN layer, and the thickness of the MgN layer is 2-10 nm.

Preferably, the P-type layer is an Mg-InGaN layer grown under a specific growth condition by metal organic vapor phase epitaxy deposition, and the thickness of the P-type layer is 50-200 nm.

Preferably, the ratio of N2/H2 is gradually reduced during the growth of the P-type layer, and the temperature is gradually increased from 1/2 → 1/16 to 700 → 900 deg.

The enhanced HEMT device structure can be obtained by adopting the following method:

(1) providing a substrate, wherein the substrate is used for extending a gallium nitride film and comprises insulating or semi-insulating materials such as sapphire, silicon carbide, gallium nitride, diamond and the like, and the size range is 2-8 inch;

(2) growing a nucleating layer at the temperature of 400-700 ℃, wherein the nucleating layer can be grown by any one or combination of ALN, ALGaN and GAN, and the total thickness of the nucleating layer is 10-50 nm;

(3) growing a buffer layer on the nucleation layer, wherein the buffer layer is made of gallium nitride materials, the growth temperature is 900-1120, and the thickness of the buffer layer is 0.5-2 um;

(4) continuing to grow an unintentionally doped gallium nitride high-resistance layer on the buffer layer, wherein the thickness of the high-resistance layer ranges from 1um to 5um, and the growth temperature is 1120-1150 ℃;

(5) growing a gallium nitride channel layer on the high-resistance layer, wherein the growth is finished by introducing triethyl gallium through metal organic vapor phase epitaxy deposition at a low growth speed, and the channel layer with better lattice quality is ensured to grow; the thickness range of the channel layer is 50-200nm, and the length speed is 0.5-1.5 um/h;

(6) growing an aluminum indium nitrogen barrier layer on the channel layer, wherein the structural formula of the aluminum indium nitrogen barrier layer is AlInN, the thickness of the aluminum indium nitrogen barrier layer is 5-35nm, the aluminum indium nitrogen barrier layer grows at the temperature of 700-900 ℃ and the pressure of 40-100 torr, and the ALInN layer with a relatively flat surface can be obtained under the growth condition;

(7) inserting an insertion layer, namely a MgN layer, on the channel layer, wherein the thickness of the MgN layer is 2-10 nm;

(8) and growing a P-type layer on the insertion layer, wherein the growth atmosphere N2/H2 is buffered from 1/2 to 1/16, and the Mg-InGaN layer grows at the temperature of 730 → 850 ℃ and has the thickness of 50-200 nm.

Compared with the prior art, the structure of the invention has the following advantages: a new structure and a growing method are provided, so that the epitaxial preparation of the enhancement type HEMT device is realized, and the stability of the performance of the enhancement type HEMT device is ensured. The main technology comprises the following steps: a high-quality channel layer grown from low-length triethyl gallium; the ALInN barrier layer with a relatively flat surface is grown under a specific condition; capturing partial defects in the barrier layer by inserting an MgN layer and improving the doping of Mg by diffusion of Mg atoms; increasing the incorporation of Mg by low temperature low H2 ratio followed by a gradual temperature increase and increasing the H2 ratio can effectively increase the effective activation of the already incorporated Mg layer to achieve a high concentration of holes; the use of the In component retained because the In component acts as a catalyst for Mg activation can effectively improve the activation of Mg and can reduce band bending of the barrier layer. The new structure and the long method can effectively improve the characteristics of the HEMT device and are suitable for the application of high-voltage high-power electronic devices.

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 graph showing the result of testing the hole concentration of the P-type layer of the epitaxial layer of the GaN device prepared by the method of the invention.

Wherein: a substrate L1, a low-temperature nucleation layer L2, a buffer layer L3, a high-resistance layer L4, a channel layer L5, a barrier layer L6, an insertion layer L7 and a P-type layer L8.

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 enhancement type HEMT device structure, which comprises a substrate L1, a low-temperature nucleation layer L2, a buffer layer L3, a high-resistance layer L4, a channel layer L5, a barrier layer L6, an insertion layer L7 and a P-type layer L8 which are sequentially arranged from bottom to top, and is specifically prepared by adopting the following method: