A `Self-Body-Biased' SOI MOSFET: A Novel Body-Voltage-Controlled SOI MOSFET for Low Voltage Applications

Abstract

A new silicon-on-insulator metal-oxide-semiconductor field effect transistor (SOI MOSFET) structure utilizing a novel body potential control scheme is proposed and studied by simulation. In the `ON' state its body potential is electrically isolated from the external body terminal by a gate depletion layer, and is controlled automatically through its drain current and drain voltage. More than 30% improvement in its current drivability over bulk counterparts is predicted. Mixed-mode simulation shows that a complementary MOS (CMOS) inverter composed of the proposed devices has a much shorter propagation delay than that in the case of a bulk CMOS inverter. Simulation results also reveal that there is no history effect in its propagation delay whereas a strong history effect exists in conventional floating-body counterparts. This is because the proposed device in the `OFF' state is functionally equivalent to a body-tied partially-depleted SOI MOSFET, allowing excess majority carriers, which are the main cause of the `history effect', to be swept away from the body terminal every time it goes to the `OFF' state.