A floating RESURF (FRESURF) LD-MOSFET device concept

This letter reports a novel device concept, which is an extension of the conventional reduced surface field (RESURF) concept. A heavily doped n-type floating region is introduced into the conventional device structure which allows the breakdown capability of the device to be increased significantly while at the same time making it high-side capable. This floating RESURF (FRESURF) device concept allows the realization of significantly higher breakdown voltage in a thin epitaxy based power integrated circuit (IC) technology. A FRESURF lateral double-diffused power MOS transistor is designed, fabricated and reported for the first time with breakdown voltages as high as 90 V as opposed to 55 V obtained from conventional device sharing same process and drift region doping.