Effect of interface states on the dc characteristics of short channel metal-semiconductor field effect transistor

The short channel effect in a MESFET structure has been studied taking into consideration the effect of interface states and the presence of a residual oxide layer at the interface. The study reveals a considerable effect of interface states on the dc channel current and saturation transconductance of the device. The expression for saturation transconductance derived in this work shows explicit dependences on interfacial parameters unlike the conventional expression frequently used for simulation. It is shown that the characteristics are limited by pinning caused by the high density of interface states.