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CN-122028462-A - GaN HEMT material epitaxial structure based on Si substrate and growth method thereof

CN122028462ACN 122028462 ACN122028462 ACN 122028462ACN-122028462-A

Abstract

The invention relates to the technical field of epitaxial growth of semiconductor materials, and discloses a GaN HEMT material epitaxial structure based on a Si substrate and a growth method thereof. The GaN-based light-emitting diode comprises a Si substrate, an AlN nucleation layer, a first AlN/In x Al 1‑x N superlattice layer, a second AlN/In y Al 1‑y N superlattice layer, an Al z Ga 1‑z N buffer layer, a GaN channel layer and a barrier layer from bottom to top. The x of the first AlN/In x Al 1‑x N superlattice layer is between 0.01 and 0.2, the y of the second AlN/In y Al 1‑y N superlattice layer is between 0.01 and 0.3, the z of the Al z Ga 1‑z N buffer layer is between 0.01 and 0.3, and In order to make the second AlN/In y Al 1‑y N superlattice layer be under compressive stress, the average In component of the second AlN/In y Al 1‑y N superlattice layer is larger than the In component of the first AlN/In x Al 1‑x N superlattice layer. According to the invention, two layers of AlN/InAlN superlattice with different In components and an Al z Ga 1‑z N buffer layer are adopted as stress regulating layers, so that mismatch stress between a Si substrate and GaN can be effectively compensated, the warping of an epitaxial wafer is reduced, the generation of dislocation is inhibited, and the quality of a material is improved.

Inventors

  • YANG QIANKUN
  • PENG DAQING
  • LI CHUANHAO
  • LI ZHONGHUI

Assignees

  • 中国电子科技集团公司第五十五研究所

Dates

Publication Date
20260512
Application Date
20260122

Claims (9)

  1. 1. The GaN HEMT material epitaxial structure based on the Si substrate is characterized by sequentially comprising the Si substrate, an AlN nucleation layer, a first AlN/In x Al 1-x N superlattice layer, a second AlN/In y Al 1-y N superlattice layer, an Al z Ga 1-z N buffer layer, a GaN channel layer and a barrier layer from bottom to top, wherein the first AlN/In x Al 1-x N superlattice layer is formed by periodically alternately growing AlN layers and In x Al 1-x N layers, x is between 0.01 and 0.2, the second AlN/In y Al 1-y N superlattice layer is formed by periodically alternately growing AlN layers and In y Al 1-y N layers, y is between 0.01 and 0.3, and z of the Al z Ga 1-z N buffer layer is between 0.01 and 0.3.
  2. 2. The GaN HEMT material epitaxial structure of claim 1, wherein the Si substrate is a low-resistance Si substrate or a high-resistance Si substrate.
  3. 3. The GaN HEMT material epitaxial structure based on the Si substrate of claim 1, wherein the average In composition of the second AlN/In y Al 1-y N superlattice layer is greater than that of the first AlN/In x Al 1-x N superlattice layer, and the average In composition of the second AlN/In y Al 1-y N superlattice layer is less than 0.17.
  4. 4. The GaN HEMT material epitaxial structure based on the Si substrate according to claim 1, wherein the period number of the first AlN/In x Al 1-x N superlattice layer is 1-100, the AlN thickness is 0.5-15nm and the In x Al 1-x N thickness is 0.5-50nm In each period.
  5. 5. The GaN HEMT material epitaxial structure based on the Si substrate according to claim 1, wherein the period number of the second AlN/In y Al 1-y N superlattice layer is 1-100, the AlN thickness is 0.5-10nm and the In y Al 1-y N thickness is 0.5-50nm.
  6. 6. The GaN HEMT material epitaxial structure based on the Si substrate of claim 1, wherein the thickness of the Al z Ga 1-z N buffer layer is 10-2000nm, and the thickness of the GaN channel layer is 50-2000nm.
  7. 7. The GaN HEMT material epitaxial structure based on the Si substrate of claim 1, wherein the materials of the Al z Ga 1-z N buffer layer and the GaN channel layer further comprise impurities such as doping C, fe to improve the voltage endurance capability.
  8. 8. The GaN HEMT material epitaxial structure based on the Si substrate according to claim 1, wherein the material of the barrier layer is any one or a combination of AlGaN, inAlN, alN, inAlGaN materials, and the thickness is 3-30nm.
  9. 9. A method for growing an epitaxial structure of a GaN HEMT material on a Si substrate according to any one of claims 1-8, comprising the steps of: 1) A Si substrate is selected and placed on a reaction chamber base in metal organic chemical vapor deposition equipment to carry out epitaxial growth; 2) Introducing hydrogen, setting the pressure of a reaction chamber to be 50-500 torr, setting the temperature to be 900-1100 ℃, baking the substrate for 5-15 minutes, and removing oxides on the surface of the substrate; 3) Setting the temperature to 600-1000 ℃, introducing 5-200sccm TMAL, and pre-paving aluminum for 3-150s; 4) Setting the pressure of the reaction chamber at 50-500torr, setting the temperature at 600-1200 ℃, introducing TMAL and NH 3 , and growing an AlN nucleation layer with the thickness of 30-300 nm; 5) The pressure of the reaction chamber is set to be 50-500torr, the temperature is set to be 600-1050 ℃, TMAL and NH 3 are continuously introduced, TMIn is introduced at intervals, and a first AlN/In x Al 1-x N superlattice layer is grown; 6) The pressure of the reaction chamber is set to be 50-500torr, the temperature is set to be 600-1000 ℃, TMAL and NH 3 are continuously introduced, TMIn is introduced at intervals, and a second AlN/In y Al 1-y N superlattice layer is grown; 7) The pressure of the reaction chamber is set to be 50-500torr, the temperature is set to be 900-1100 ℃, TMGa, TMAL and NH 3 are introduced, and an Al z Ga 1-z N buffer layer is grown; 8) The pressure of the reaction chamber is set to be 50-500torr, the temperature is set to be 900-1100 ℃, TMGa and NH 3 are introduced, and a GaN channel layer is grown; 9) The pressure of the reaction chamber is set to be 50-500torr, the temperature is set to be 900-1100 ℃, TMGa, TMAL and NH 3 are introduced, and an AlGaN barrier layer is grown; 10 And (3) taking out the epitaxial wafer after cooling.

Description

GaN HEMT material epitaxial structure based on Si substrate and growth method thereof Technical Field The invention belongs to the technical field of semiconductor materials and devices, and particularly relates to an epitaxial structure of a GaN HEMT material based on a Si substrate and a growth method thereof. Background Since the preparation of GaN bulk single crystal materials is very difficult, gaN single crystal thin films are generally obtained by heteroepitaxy, and commonly used substrates include Si, sapphire, siC, and the like. The Si substrate has the advantages of larger expandable wafer size, higher single crystal substrate quality and low price, and the device process is compatible with the CMOS process of the Si integrated circuit, so that the cost of large-scale manufacturing can be greatly reduced. However, epitaxial obtaining of high quality GaN materials on Si substrates presents challenges, especially with a large lattice mismatch (16.9%) and thermal expansion coefficient mismatch (56%) between GaN and Si substrates, so that the GaN epitaxial layer on Si substrate not only has a high dislocation density, but also has a large residual strain due to tensile stress caused by thermal mismatch, and even finally results in film cracking, severely affecting the performance and reliability of the device. In recent years, various methods and technical means for growing GaN and heterostructures thereof on Si substrates have been developed at home and abroad, and partial regulation and control of lattice and thermal mismatch stress have been primarily realized by introducing low-temperature AlN insertion layers, alN/GaN superlattices or AlGaN composition graded buffer layers and other technologies, but the prior art scheme still faces significant challenges in balancing material quality, stress control, radio frequency loss and the like. On the one hand, conventional superlattice buffer layers (e.g., alN/GaN superlattices) typically require higher epitaxial temperatures to promote material quality and provide greater compressive stress to GaN, but higher growth temperatures are detrimental to control material rf losses. On the other hand, although the single component gradual change buffer layer can provide certain stress compensation, the control precision and flexibility are limited, so that the residual stress of the epitaxial layer is controlled incompletely, and the warping degree and the process stability of the wafer are affected. Therefore, how to develop a novel epitaxial buffer structure, so that the novel epitaxial buffer structure can more effectively and cooperatively regulate and control stress and greatly reduce crystal defects under relatively mild growth conditions, thereby meeting the severe requirements of a radio-frequency GaN HEMT device on low loss, high mobility and high reliability, and becoming a key subject to be deeply explored and solved in the field. Disclosure of Invention Aiming at the problem of GaN stress regulation and control on a Si substrate, the invention aims to provide a GaN HEMT material epitaxial structure based on the Si substrate and a growth method thereof, and the GaN HEMT material epitaxial structure adopts an AlN/InAlN superlattice and an AlGaN layer as buffer layers, has the advantages of good stress regulation and control effect and low defect density, and the AlN/InAlN superlattice is suitable for growth at a lower temperature, is beneficial to reducing radio frequency loss, and has good application prospect. In order to solve the problems in the prior art, the invention adopts the following technical scheme: The GaN HEMT material epitaxial structure based on the Si substrate sequentially comprises the Si substrate, an AlN nucleation layer, a first AlN/In xAl1-x N superlattice layer, a second AlN/In yAl1-y N superlattice layer, an Al zGa1-z N buffer layer, a GaN channel layer and a barrier layer from bottom to top, wherein the first AlN/In xAl1-x N superlattice layer is formed by periodically and alternately growing an AlN layer and an In xAl1-x N layer, x is between 0.01 and 0.2, the second AlN/In yAl1-y N superlattice layer is formed by periodically and alternately growing an AlN layer and an In yAl1-y N layer, y is between 0.01 and 0.3, and z of the Al zGa1-z N buffer layer is between 0.01 and 0.3. Preferably, the Si substrate is a low-resistance Si substrate or a high-resistance Si substrate. Preferably, the average In composition of the second AlN/In yAl1-y N superlattice layer is greater than that of the first AlN/In xAl1-x N superlattice layer, and the average In composition of the second AlN/In yAl1-y N superlattice layer is less than 0.17. Preferably, the cycle number of the first AlN/In xAl1-x N superlattice layer is 1-100 cycles, the AlN thickness is 0.5-15nm and the In xAl1-x N thickness is 0.5-50nm In each cycle. Preferably, the cycle number of the second AlN/In yAl1-y N superlattice layer is 1-100 cycles, the AlN thickness is 0.5-10nm