Electron saturation velocity variation in InGaAs and GaAs channel MODFETs for gate length to 550 AA

MODFETs with InGaAs and GaAs channels have been fabricated with gate lengths between 2 mu m and 550 AA 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 mu m, while the transconductance and velocity of the InGaAs channel devices are nearly constant over the entire range of gate lengths. >