中国物理B ›› 2022, Vol. 31 ›› Issue (9): 97401-097401.doi: 10.1088/1674-1056/ac6743

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Physical analysis of normally-off ALD Al2O3/GaN MOSFET with different substrates using self-terminating thermal oxidation-assisted wet etching technique

Cheng-Yu Huang(黄成玉)1, Jin-Yan Wang(王金延)1,†, Bin Zhang(张斌)1, Zhen Fu(付振)2, Fang Liu(刘芳)2, Mao-Jun Wang(王茂俊)1, Meng-Jun Li(李梦军)1, Xin Wang(王鑫)1, Chen Wang(汪晨)1, Jia-Yin He(何佳音)1, and Yan-Dong He(何燕冬)1,‡   

  1. 1 School of Integrated Circuits, Peking University, Beijing 100871, China;
    2 Beijing Chip Identification Technology Co., Ltd, Beijing 102200, China
  • 收稿日期:2022-02-12 修回日期:2022-03-29 接受日期:2022-04-14 出版日期:2022-08-19 发布日期:2022-09-01
  • 通讯作者: Jin-Yan Wang, Yan-Dong He E-mail:wangjinyan@pku.edu.cn;heyd@pku.edu.cn
  • 基金资助:
    Project supported by the Research on Key Techniques in Reliability of Low Power Sensor Chip for IOTIPS and the Technology Project of Headquarters, State Grid Corporation of China(Grant No. 5700-202041397A-0-0-00).

Physical analysis of normally-off ALD Al2O3/GaN MOSFET with different substrates using self-terminating thermal oxidation-assisted wet etching technique

Cheng-Yu Huang(黄成玉)1, Jin-Yan Wang(王金延)1,†, Bin Zhang(张斌)1, Zhen Fu(付振)2, Fang Liu(刘芳)2, Mao-Jun Wang(王茂俊)1, Meng-Jun Li(李梦军)1, Xin Wang(王鑫)1, Chen Wang(汪晨)1, Jia-Yin He(何佳音)1, and Yan-Dong He(何燕冬)1,‡   

  1. 1 School of Integrated Circuits, Peking University, Beijing 100871, China;
    2 Beijing Chip Identification Technology Co., Ltd, Beijing 102200, China
  • Received:2022-02-12 Revised:2022-03-29 Accepted:2022-04-14 Online:2022-08-19 Published:2022-09-01
  • Contact: Jin-Yan Wang, Yan-Dong He E-mail:wangjinyan@pku.edu.cn;heyd@pku.edu.cn
  • Supported by:
    Project supported by the Research on Key Techniques in Reliability of Low Power Sensor Chip for IOTIPS and the Technology Project of Headquarters, State Grid Corporation of China(Grant No. 5700-202041397A-0-0-00).

摘要: Based on the self-terminating thermal oxidation-assisted wet etching technique, two kinds of enhancement mode Al$_{2}$O$_{3}$/GaN MOSFETs (metal-oxide-semiconductor field-effect transistors) separately with sapphire substrate and Si substrate are prepared. It is found that the performance of sapphire substrate device is better than that of silicon substrate. Comparing these two devices, the maximum drain current of sapphire substrate device (401 mA/mm) is 1.76 times that of silicon substrate device (228 mA/mm), and the field-effect mobility ($\mu_{\rm FEmax}$) of sapphire substrate device (176 cm$^{2}$/V$\cdot$s) is 1.83 times that of silicon substrate device (96 cm$^{2}$/V$\cdot$s). The conductive resistance of silicon substrate device is 21.2 $\Omega {\cdot }$mm, while that of sapphire substrate device is only 15.2 $\Omega {\cdot }$mm, which is 61% that of silicon substrate device. The significant difference in performance between sapphire substrate and Si substrate is related to the differences in interface and border trap near Al$_{2}$O$_{3}$/GaN interface. Experimental studies show that (i) interface/border trap density in the sapphire substrate device is one order of magnitude lower than in the Si substrate device, (ii) Both the border traps in Al$_{2}$O$_{3}$ dielectric near Al$_{2}$O$_{3}$/GaN and the interface traps in Al$_{2}$O$_{3}$/GaN interface have a significantly effect on device channel mobility, and (iii) the properties of gallium nitride materials on different substrates are different due to wet etching. The research results in this work provide a reference for further optimizing the performances of silicon substrate devices.

关键词: atomic layer deposition Al2O3/GaN MOSFET, normally-off, interface/border traps, thermal oxidation-assisted wet etching

Abstract: Based on the self-terminating thermal oxidation-assisted wet etching technique, two kinds of enhancement mode Al$_{2}$O$_{3}$/GaN MOSFETs (metal-oxide-semiconductor field-effect transistors) separately with sapphire substrate and Si substrate are prepared. It is found that the performance of sapphire substrate device is better than that of silicon substrate. Comparing these two devices, the maximum drain current of sapphire substrate device (401 mA/mm) is 1.76 times that of silicon substrate device (228 mA/mm), and the field-effect mobility ($\mu_{\rm FEmax}$) of sapphire substrate device (176 cm$^{2}$/V$\cdot$s) is 1.83 times that of silicon substrate device (96 cm$^{2}$/V$\cdot$s). The conductive resistance of silicon substrate device is 21.2 $\Omega {\cdot }$mm, while that of sapphire substrate device is only 15.2 $\Omega {\cdot }$mm, which is 61% that of silicon substrate device. The significant difference in performance between sapphire substrate and Si substrate is related to the differences in interface and border trap near Al$_{2}$O$_{3}$/GaN interface. Experimental studies show that (i) interface/border trap density in the sapphire substrate device is one order of magnitude lower than in the Si substrate device, (ii) Both the border traps in Al$_{2}$O$_{3}$ dielectric near Al$_{2}$O$_{3}$/GaN and the interface traps in Al$_{2}$O$_{3}$/GaN interface have a significantly effect on device channel mobility, and (iii) the properties of gallium nitride materials on different substrates are different due to wet etching. The research results in this work provide a reference for further optimizing the performances of silicon substrate devices.

Key words: atomic layer deposition Al2O3/GaN MOSFET, normally-off, interface/border traps, thermal oxidation-assisted wet etching

中图分类号:  (III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions)

  • 73.40.Kp
73.20.At (Surface states, band structure, electron density of states) 81.05.Ea (III-V semiconductors)