CHARACTERISTICS INCLUDING ELECTRON VELOCITY OVERSHOOT FOR 0.1-MUM-GATE-LENGTH GAAS SAINT MESFETS

Short channel effects, substrate leakage current, and average electron velocity are investigated for 0.1-µm-gate-length GaAs MESFET's fabricated using the SAINT process. The threshold-voltage shift was scaled by the aspect ratio of the channel thickness to the gate length (a/Lg). The substrate leakage current in a sub-quarter-mi-crometer MESFET is completely suppressed by the buried players and shallow n+-layers. The average electron velocity for 0.1- to 0.2-μm-gate-length FET's is estimated to be 3 x 107cm/s from the analysis of intrinsic FET parameters. This high value indicates electron velocity overshoot. Moreover, a very high fT of 93.1 GHz has been obtained by the 0.1-μm SAINT MESFET. ©1990 IEEE