Patent ID: 6213869
Filing Date: 2001-04-10
Classification: H01L

Abstract:
A MOSFET (Metal Oxide Semiconductor Field Effect Transistor) type device having higher drive current when turned on and having lower steady state power dissipation when turned off, said MOSFET type device being fabricated on a semiconductor substrate, and said MOSFET type device comprising:a floating body region that is electrically isolated from said semiconductor substrate;a drain region abutting said floating body region;a source region abutting said floating body region;a gate formed on a gate insulator disposed on top of said floating body region between said drain region and said source region;a coupling capacitor that is operatively coupled between said gate and said floating body region, wherein said coupling capacitor has a capacitance of C.sub.C ;and wherein said floating body region, said drain region, said source region, and said gate form a MOSFET (Metal Oxide Semiconductor Field Effect Transistor);and wherein said drain region forms a collector of a BJT (Bipolar Junction Transistor), said floating body region forms a base of said BJT, and said source region forms an emitter of said BJT;and wherein said MOSFET is turned on when a voltage change of V.sub.dd is applied on said gate with respect to said source region; andmeans for biasing said floating body region to an initial voltage of V.sub.body(I) before the voltage change of V.sub.dd is applied on the gate with respect to the source of the MOSFET when the MOSFET is switched to turn on from being turned off;and wherein said capacitance, C.sub.C, of said coupling capacitor is designed such that (V.sub.body(I) +(C.sub.C *V.sub.dd)/(C.sub.C +C.sub.P)>V.sub.C to provide a positive voltage at said floating body region with respect to said source region when said MOSFET is turned on, wherein C.sub.P is a capacitance of an effective parasitic capacitor at said floating body region, and wherein V.sub.C is a clamping voltage of a diode formed by said base and said emitter of said BJT.