中国物理B ›› 2026, Vol. 35 ›› Issue (5): 57108-057108.doi: 10.1088/1674-1056/ae3c94

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Design and optimization of area-selective carrier modulation in β-Ga2O3 through high temperature oxygen annealing

Qiuyan Li(李秋艳)1, Qiming He(何启鸣)2, Jinyang Liu(刘金杨)1, Xuanze Zhou(周选择)1, Guangwei Xu(徐光伟)1,†, and Shibing Long(龙世兵)1   

  1. 1 School of Microelectronics, University of Science and Technology of China, Hefei 230026, China;
    2 School of Electronic Information Engineering, Beihang University, Beijing 100191, China
  • 收稿日期:2025-12-17 修回日期:2026-01-13 接受日期:2026-01-23 发布日期:2026-04-29
  • 通讯作者: Guangwei Xu,E-mail:xugw@ustc.edu.cn E-mail:xugw@ustc.edu.cn
  • 基金资助:
    This work was supported by the National Natural Science Foundation of China (Grant Nos. 61925110, U23A20358, and 62234007), the University of Science and Technology of China (USTC) Research Funds of the Double First-Class Initiative (Grant Nos. YD2100002009 and YD2100002010), the Collaborative Innovation Program of Hefei Science Center, Chinese Academy of Sciences (CAS) (Grant No. 2022HSCCIP024), the JieBang Headed Project of Changsha City Hunan Province (Grant No. kq2301006), and the Opening Project of and the Key Laboratory of Nanodevices and Applications in Suzhou Institute of Nano-Tech and Nano-Bionics of CAS (Grant No. SZLAB-1208-2024-ZD012).

Design and optimization of area-selective carrier modulation in β-Ga2O3 through high temperature oxygen annealing

Qiuyan Li(李秋艳)1, Qiming He(何启鸣)2, Jinyang Liu(刘金杨)1, Xuanze Zhou(周选择)1, Guangwei Xu(徐光伟)1,†, and Shibing Long(龙世兵)1   

  1. 1 School of Microelectronics, University of Science and Technology of China, Hefei 230026, China;
    2 School of Electronic Information Engineering, Beihang University, Beijing 100191, China
  • Received:2025-12-17 Revised:2026-01-13 Accepted:2026-01-23 Published:2026-04-29
  • Contact: Guangwei Xu,E-mail:xugw@ustc.edu.cn E-mail:xugw@ustc.edu.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (Grant Nos. 61925110, U23A20358, and 62234007), the University of Science and Technology of China (USTC) Research Funds of the Double First-Class Initiative (Grant Nos. YD2100002009 and YD2100002010), the Collaborative Innovation Program of Hefei Science Center, Chinese Academy of Sciences (CAS) (Grant No. 2022HSCCIP024), the JieBang Headed Project of Changsha City Hunan Province (Grant No. kq2301006), and the Opening Project of and the Key Laboratory of Nanodevices and Applications in Suzhou Institute of Nano-Tech and Nano-Bionics of CAS (Grant No. SZLAB-1208-2024-ZD012).

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摘要： Carrier modulation in beta-gallium oxide ($\beta $-Ga$_{2}$O$_{3}$) films through an oxygen annealing method is systematically investigated, including annealing time and annealing cap layer (ACL) design. Capacitance-voltage measurement conducted on vertical SBD structures was used to evaluate the carrier concentration after annealing. The formation of a “surface layer” may suppress the diffusion of oxygen species as the annealing time increases. An 8-hour annealing time resulted in a carrier modulation with an approximately 3-μm-deep low-carrier-concentration layer. The annealing cap layer, consisting of poly-Si and SiO$_{2}$, was deposited and patterned to achieve area-selective carrier modulation in $\beta $-Ga$_{2}$O$_{3}$. The effective thickness of poly-Si for blocking oxygen diffusion was confirmed by scanning electron microscopy (SEM) for the first time. A definite thickness of SiO$_{2}$ served as both etching stop layer and lift-off layer for poly-Si. According to simulation results, the non-ideal surface caused extra high peak electric field in the $\beta $-Ga$_{2}$O$_{3}$ device. A combination of an optimized dry etching method and low-compressive-stress deposition technology was employed to eliminate the bird's beak-like shape structure that appeared at the edges of the patterns and bulges on the $\beta $-Ga$_{2}$O$_{3}$ surface after annealing. The feasibility of the carrier modulation technology enables the diversity of $\beta $-Ga$_{2}$O$_{3}$ devices fabrication.

关键词: Ga$_{2}$O$_{3}$, oxygen annealing, carrier modulation, power device

Abstract: Carrier modulation in beta-gallium oxide ($\beta $-Ga$_{2}$O$_{3}$) films through an oxygen annealing method is systematically investigated, including annealing time and annealing cap layer (ACL) design. Capacitance-voltage measurement conducted on vertical SBD structures was used to evaluate the carrier concentration after annealing. The formation of a “surface layer” may suppress the diffusion of oxygen species as the annealing time increases. An 8-hour annealing time resulted in a carrier modulation with an approximately 3-μm-deep low-carrier-concentration layer. The annealing cap layer, consisting of poly-Si and SiO$_{2}$, was deposited and patterned to achieve area-selective carrier modulation in $\beta $-Ga$_{2}$O$_{3}$. The effective thickness of poly-Si for blocking oxygen diffusion was confirmed by scanning electron microscopy (SEM) for the first time. A definite thickness of SiO$_{2}$ served as both etching stop layer and lift-off layer for poly-Si. According to simulation results, the non-ideal surface caused extra high peak electric field in the $\beta $-Ga$_{2}$O$_{3}$ device. A combination of an optimized dry etching method and low-compressive-stress deposition technology was employed to eliminate the bird's beak-like shape structure that appeared at the edges of the patterns and bulges on the $\beta $-Ga$_{2}$O$_{3}$ surface after annealing. The feasibility of the carrier modulation technology enables the diversity of $\beta $-Ga$_{2}$O$_{3}$ devices fabrication.

Key words: Ga$_{2}$O$_{3}$, oxygen annealing, carrier modulation, power device

中图分类号:  (Impurity and defect levels)

  • 71.55.-i
73.61.-r (Electrical properties of specific thin films) 85.30.-z (Semiconductor devices)