Investigation of impact ionization from InxGa1-xAs to InAs Channel HEMTs for high speed and low power applications

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 performance degradation were observed on the DC measurement and RF characteristics caused by impact ionization at different drain bias, >0.8 V (InAs/In
_0.7
Ga
_0.3
As), >1 V (In
_0.7
Ga
_0.3
As) and >1.5 V (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.