Comparative Study on Dynamic Characteristics of GaN HEMT at 300K and 150K

Abstract

Dynamic characteristics of GaN HEMT grown on a native substrate were systematically investigated at 300K and 150K. Transfer and output characteristics of the GaN HEMT were measured after various off-state stressing conditions and recovery durations. In addition, a high-speed scheme was employed to finish the measurement within 75 μs, and to ensure maximum preservation of stressing/recovery consequences. The threshold voltage instability and current collapse commonly observed at room temperature were mostly diminished at 150K, which was attributed to reduced number of electrons through the metal-semiconductor contact and insufficient number of carriers overcoming the capture potential barrier. Two pulsed I-V measurements, including evaluations with various off-state quiescent bias points and "on-the-fly" on-resistance sampling, confirmed an inefficient electron capture process at 150K, with a time constant larger than dozens of seconds. The output characteristic comparison between hard switch and soft switch at 150K provided direct experimental evidence for electron capture promotion by hot carriers.

Dynamic Characteristics of GaN MISHEMT With 5-nm In-Situ SiNx Dielectric Layer

“…And the saturation current 6 > REPLACE THIS LINE WITH YOUR MANUSCRIPT ID NUMBER (DOUBLE-CLICK HERE TO EDIT) < showed a steady reduction with DGD = -4μs, compared with soft-switching. This additional current collapse was associated with high energy electrons [38,39,44]. During hard-switching, the device was in large drain bias condition when Vgs crossed the threshold voltage, resulting in the generation of high energy electrons.…”

“…SiNx/AlGaN/GaN MISHEMT, including transfer characteristics, output properties, threshold voltage instability, and pulsed I-V characteristics were measured using semiconductor device analyzer. The principles and waveforms of stress-recovery-measurement, double pulse measurement, and drain current transient measurement with pre-stressing could be found elsewhere [38][39][40][41]. The positive shift of Vth was related to trap states in the gate dielectric and at the insulator/AlGaN interface.…”

DC and low-frequency noise characteristics of GaN-based HEMTs under cryogenic temperatures

“…Apart from these traditional devices, wide bandgap semiconductor GaNbased high-electron-mobility transistors (HEMTs) recently have emerged as a promising candidate for the cryo-systems thanks to their superior material and device properties [6][7][8]. Especially, the conductive channel of the GaN-based HEMTs consists of the high-concentration two-dimensional electron gas (2DEG) which is spontaneously formed by the polarization effects [9]. Therefore, the influence of freezing effects on the electron concentration of such 2DEG would be negligible at extremely low temperatures, leading to large output current and fast switching speed under cryogenic environments [10,11].…”

“…Therefore, the influence of freezing effects on the electron concentration of such 2DEG would be negligible at extremely low temperatures, leading to large output current and fast switching speed under cryogenic environments [10,11]. Recently, several studies have reported the GaN-based cryo-HEMTs by analyzing their device-level and circuit-level performance at temperatures (T) of ∼100 K. The important research topics such as hot carriers, kink effects, switching loss, and phase compression under cryogenic environments, have also been elaborately discussed [9][10][11][12].…”