3000 V class MOSFET switch for Semiconductor Relay using MEMS process

To develop a small and high-breakdown voltage semiconductor relay for scanners in recorders, we have developed a MOSFET (metal-oxide-semiconductor field-effect transistor) with a new three-dimensional termination as a switching device. The termination consists of deep-etched side-walls and junctions on them. Using this structure, a 3200 V MOSFET measuring just 1.7 mm-square has been achieved for the first time in the world. We used a MEMS (micro electro mechanical systems) process to etch a 400-µm groove, which is several ten to several hundred times as deep as that formed by a normal dry etching process.