Intrinsic Response Time of Normally Off MESFET's of GaAs, Si, and InP

A response time of normally off MESFET's for high-speed Iogic circuits made of GaAs, Si, and InP was calculated using a two-dimensional numerical analysis. The results indicate that GaAs is the best material among them. The step response of the InP FET is not as fast as expected from v/E characteristics due to low electric field in the channel for low-power logic operation of a normally off FET.