Investigation of Impact Ionization from In(x)Ga(1-x)As to InAs Channel HEMTs for High Speed and Low Power Applications

Abstract

80-nm high electron mobility transistors (HEMTs) with different Indium content in In(x)Ga(1-x)As channel from 52%, 70% to 100% have been fabricated. Device performances degradation were observed on the DC measurement and RF characteristics caused by impact ionization at different drain bias, >0.8V (InAs/In(0.7)Ga(0.3)As), > 1V (In(0.7)Ga(0.3)As) and > 1.5V (In(0.52)Ga(0.48)As), respectively. The impact ionization phenomenon should be avoided for high speed, low power application because it limits the highest drain bias of the device which in turn limits the drift velocity under specific applied electric field.