A two-dimensional analytical subthreshold behavior model for short-channel dual-material gate (DMG) AlGaAs/GaAs HFETs

Abstract

Based on the exact solution of the two-dimensional Poisson's equation, a new analytical model for the subthreshold behavior of a short-channel dual-material gate(DMG) AIGaAs/GaAs HFET's is developed. The model illustrates how the device parameters affect the subthreshold characteristics. Both thin doped AIGaAs body and thin intrinsic AIGaAs spacer can greatly suppress the SCEs and reduce the degradation of threshold voltage and subthreshold swing. Besides, by either tuning a larger ratio of control gate to screen gate length or adjusting work function ofthe screen gate to a higher value, the DMG structure can lessen the drain-induced barrier 10wering(DIBL) and degrade the subthreshold behavior. The model is verified by its good agreement with the numerical simulation of the device simulator.