Field effect transistors having tapered gate electrodes for providing high breakdown voltage capability and methods of forming same

摘要

Field effect transistors having tapered gate electrodes include a body region of first conductivity type extending to a surface of a semiconductor substrate. Source and drain regions of second conductivity type are formed in the substrate and a gate electrode is formed on a portion of the surface extending opposite the body region and between the source and drain regions. A gate electrode insulating layer is also disposed between the gate electrode and the surface. To improve the transistor's withstand voltage capability by reducing field crowding, the gate electrode insulating layer is preferably formed to have a tapered thickness which increases in a direction from the source region to the drain region, and to reduce on-state resistance the drain region is formed in a self-aligned manner to the gate electrode.