中国物理B ›› 2011, Vol. 20 ›› Issue (1): 18101-018101.doi: 10.1088/1674-1056/20/1/018101

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Investigation of AlGaN/GaN fluorine plasma treatment enhancement-mode high electronic mobility transistors by frequency-dependent capacitance and conductance analysis

全思, 郝跃, 马晓华, 于惠游   

  1. Key Laboratory of Wide Band Gap Semiconductor Materials and Devices, Institute of Microelectronics, Xidian University, Xi'an 710071, China
  • 收稿日期:2010-03-11 修回日期:2010-07-07 出版日期:2011-01-15 发布日期:2011-01-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 60736033) and the Fundamental Research Funds for the Central Universities (Grant No. JY10000904009).

Investigation of AlGaN/GaN fluorine plasma treatment enhancement-mode high electronic mobility transistors by frequency-dependent capacitance and conductance analysis

Quan Si(全思),Hao Yue(郝跃),Ma Xiao-Hua(马晓华),and Yu Hui-You(于惠游)   

  1. Key Laboratory of Wide Band Gap Semiconductor Materials and Devices, Institute of Microelectronics, Xidian University, Xi'an 710071, China
  • Received:2010-03-11 Revised:2010-07-07 Online:2011-01-15 Published:2011-01-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 60736033) and the Fundamental Research Funds for the Central Universities (Grant No. JY10000904009).

摘要: This paper reports fluorine plasma treatment enhancement-mode HEMTs (high electronic mobility transistors) EHEMTs and conventional depletion-mode HEMTs DHEMTs fabricated on one wafer using separate litho-photography technology. It finds that fluorine plasma etches the AlGaN at a slow rate by capacitance--voltage measurement. Using capacitance--frequency measurement, it finds one type of trap in conventional DHEMTs with τT=(0.5-6) ms and DT= (1 - 5) × 1013 cm-2·eV-1. Two types of trap are found in fluorine plasma treatment EHEMTs, fast with τT(f)=(0.2-2) μs and slow with τT(s)=(0.5-6) ms. The density of trap states evaluated on the EHEMTs is DT(f)=(1 - 3) × 1012 cm-2·eV-1 and DT(s)=(2 - 6) × 1012 cm-2·eV-1 for the fast and slow traps, respectively. The result shows that the fluorine plasma treatment reduces the slow trap density by about one order, but introduces a new type of fast trap. The slow trap is suggested to be a surface trap, related to the gate leakage current.

关键词: AlGaN/GaN, enhancement-mode high electronic mobility transistors, fluorine plasma treatment, frequency dependent capacitance and conductance

Abstract: This paper reports fluorine plasma treatment enhancement-mode HEMTs (high electronic mobility transistors) EHEMTs and conventional depletion-mode HEMTs DHEMTs fabricated on one wafer using separate litho-photography technology. It finds that fluorine plasma etches the AlGaN at a slow rate by capacitance–voltage measurement. Using capacitance–frequency measurement, it finds one type of trap in conventional DHEMTs with $\tau$T=(0.5–6) ms and DT= (1–5) × 1013 cm-2·eV-1. Two types of trap are found in fluorine plasma treatment EHEMTs, fast with τT(f)=(0.2–2) μs and slow with $\tau$T(s)=(0.5–6) ms. The density of trap states evaluated on the EHEMTs is DT(f)=(1–3) × 1012 cm-2·eV-1 and DT(s)=(2–6) × 1012 cm-2·eV-1 for the fast and slow traps, respectively. The result shows that the fluorine plasma treatment reduces the slow trap density by about one order, but introduces a new type of fast trap. The slow trap is suggested to be a surface trap, related to the gate leakage current.

Key words: AlGaN/GaN, enhancement-mode high electronic mobility transistors, fluorine plasma treatment, frequency dependent capacitance and conductance

中图分类号:  (III-V semiconductors)

  • 81.05.Ea
85.30.De (Semiconductor-device characterization, design, and modeling) 85.50.-n (Dielectric, ferroelectric, and piezoelectric devices)