Time-dependent device characteristics in InAs/AlSb HEMTs

This study investigates the device characteristics of InAs/AlSb HEMTs subjected to different periods of time storage in atmospheric ambiance after fabrication. Devices that have undergone 6 months of storage exhibit an increase of saturation drain current (IDSS), increase of peak transconductance, decrease of gate leakage (IG) and shifts of threshold voltage (Vth). The charge trapping effect was investigated by using a pulsed ID–VDS measurement, indicating that surface traps or defects were generated in the device that had undergone a 6-month storage. The decrease of IG and shifts of Vth were found to correlate with material oxidization in the gate to the channel region, where an oxygen signal was detected by energy-dispersive analysis with X-ray (EDAX). Variances of gate capacitances (Cgs) extracted by the small-signal model were also used to justify the shifts of Vth.

► This study first investigates InAs/AlSb HEMTs subjected to different periods of time storage.
► The surface charge trapping effect was investigated by using pulsed ID–VDS measurement.
► The decrease of IG and shifts of Vth were found to correlate with material degradation in the gate to the channel region.