US Patent 7535055 Trench transistor

A trench transistor is disclosed. One embodiment has an active zone enclosed by an edge trench, wherein an edge electrode at gate potential is embedded into the edge trench, and the active zone has a mesa structure at least partly adjoining the edge trench. That region of the mesa structure which adjoins the edge trench is at least partly electrically deactivated by virtue of the fact that within this deactivated region a) the mesa structure is covered with a mesa insulation layer, and b) no source zone is provided.