中国物理B ›› 2011, Vol. 20 ›› Issue (2): 27304-027304.doi: 10.1088/1674-1056/20/2/027304

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Characterization of Al2O3/GaN/AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors with different gate recess depths

杨丽媛1, 杨凌1, 全思1, 王昊1, 张进成1, 郝跃1, 潘才渊2, 于惠游2, 马晓华3   

  1. (1)Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China; (2)School of Technical Physics, Xidian University, Xi'an 710071, China; (3)School of Technical Physics, Xidian University, Xi'an 710071, China; Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China
  • 收稿日期:2010-08-14 修回日期:2010-10-20 出版日期:2011-02-15 发布日期:2011-02-15
  • 基金资助:
    Project supported by the National Key Science and Technology Special Project, China (Grant No. 2008ZX01002-002), and the National Natural Science Foundation of China (Grant No. 60736033).

Characterization of Al2O3/GaN/AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors with different gate recess depths

Ma Xiao-Hua(马晓华)a)b)†, Pan Cai-Yuan(潘才渊) a), Yang Li-Yuan(杨丽媛)b), Yu Hui-You(于惠游)a), Yang Ling(杨凌)b), Quan Si(全思)b), Wang Hao(王昊)b), Zhang Jin-Cheng(张进成) b), and Hao Yue(郝跃)b)   

  1. a School of Technical Physics, Xidian University, Xi'an 710071, China; b Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China
  • Received:2010-08-14 Revised:2010-10-20 Online:2011-02-15 Published:2011-02-15
  • Supported by:
    Project supported by the National Key Science and Technology Special Project, China (Grant No. 2008ZX01002-002), and the National Natural Science Foundation of China (Grant No. 60736033).

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摘要： In this paper, in order to solve the interface-trap issue and enhance the transconductance induced by high-k dielectric in metal--insulator--semiconductor (MIS) high electron mobility transistors (HEMTs), we demonstrate better performances of recessed-gate Al2O3 MIS-HEMTs which are fabricated by Fluorine-based Si3N4 etching and chlorine-based AlGaN etching with three etching times (15 s, 17 s and 19 s). The gate leakage current of MIS-HEMT is about three orders of magnitude lower than that of AlGaN/GaN HEMT. Through the recessed-gate etching, the transconductance increases effectively. When the recessed-gate depth is 1.02 nm, the best interface performance with tauit=(0.20--1.59) μs and Dit=(0.55--1.08)×1012 cm-2·eV-1 can be obtained. After chlorine-based etching, the interface trap density reduces considerably without generating any new type of trap. The accumulated chlorine ions and the N vacancies in the AlGaN surface caused by the plasma etching can degrade the breakdown and the high frequency performances of devices. By comparing the characteristics of recessed-gate MIS-HEMTs with different etching times, it is found that a low power chlorine-based plasma etching for a short time (15 s in this paper) can enhance the performances of MIS-HEMTs effectively.

关键词: AlGaN/GaN gate-recessed MIS-HEMT, frequency-dependent capacitance and conductance, drain current injection technique, knee resistance

Abstract: In this paper, in order to solve the interface-trap issue and enhance the transconductance induced by high-k dielectric in metal--insulator--semiconductor (MIS) high electron mobility transistors (HEMTs), we demonstrate better performances of recessed-gate Al2O3 MIS-HEMTs which are fabricated by Fluorine-based Si3N4 etching and chlorine-based AlGaN etching with three etching times (15 s, 17 s and 19 s). The gate leakage current of MIS-HEMT is about three orders of magnitude lower than that of AlGaN/GaN HEMT. Through the recessed-gate etching, the transconductance increases effectively. When the recessed-gate depth is 1.02 nm, the best interface performance with $\tau$it=(0.20-1.59) μs and Dit=(0.55-1.08)×1012 cm-2·eV-1 can be obtained. After chlorine-based etching, the interface trap density reduces considerably without generating any new type of trap. The accumulated chlorine ions and the N vacancies in the AlGaN surface caused by the plasma etching can degrade the breakdown and the high frequency performances of devices. By comparing the characteristics of recessed-gate MIS-HEMTs with different etching times, it is found that a low power chlorine-based plasma etching for a short time (15 s in this paper) can enhance the performances of MIS-HEMTs effectively.

Key words: AlGaN/GaN gate-recessed MIS-HEMT, frequency-dependent capacitance and conductance, drain current injection technique, knee resistance

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

  • 73.40.Kp
73.61.Ey (III-V semiconductors) 78.30.Fs (III-V and II-VI semiconductors)