Electron saturation velocity variation in InGaAs and GaAs channelMODFETs for gate length to 550 A

MODFETs with InGaAs and GaAs channels have been fabricated with gate lengths between 2 mum and 550 A and have been DC characterized at room temperature. An effective electron saturation velocity was calculated for each device from the peak transconductance. The GaAs channel devices show a peak in the transconductance and saturation velocity at a gate length of approximately 0.15 mum, while the transconductance and velocity of the InGaAs channel devices are nearly constant over the entire range of gate lengths