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 TT = (0.5 - 6) ms and DT : (1 - 5)×10^13 cm^-2. eV^-1. Two types of trap are found in fluorine plasma treatment EHEMTs, fast with TW(f)= (0.2 - 2) μs and slow with TT(s) = (0.5 - 6) ms. The density of trap states evaluated on the EHEMTs is Dw(f) : (1 - 3) × 10^12 cm^-2. eV^-1 and DT(s) =(2 - 6) × 10^12 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.
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 TT = (0.5 - 6) ms and DT : (1 - 5)×10^13 cm^-2. eV^-1. Two types of trap are found in fluorine plasma treatment EHEMTs, fast with TW(f)= (0.2 - 2) μs and slow with TT(s) = (0.5 - 6) ms. The density of trap states evaluated on the EHEMTs is Dw(f) : (1 - 3) × 10^12 cm^-2. eV^-1 and DT(s) =(2 - 6) × 10^12 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.
基金
Project supported by the National Natural Science Foundation of China(Grant No.60736033)
the Fundamental Research Funds for the Central Universities(Grant No.JY10000904009)