Raised semiconductor mos transistor with improved transistor

Abstract

A semiconductor device including a semiconductor substrate having thereon an element region having a surface, an element separating insulating film having an upper surface adjacent to opposing lateral sides of the element region, a silicon epitaxial layer having an upper surface formed on the surface of the element region, a polysilicon layer having an upper surface formed on the element separating film and connected to the silicon epitaxial layer, a gate insulating film and a gate electrode formed on the silicon epitaxial layer, and impurity doped source and drain regions formed in the silicon epitaxial layer. Furthermore, the upper surface of the silicon epitaxial layer is higher than or at the same level as the upper surface of the polysilicon layer. This is done by forming the polysilicon layer on a recessed portion of the element separating insulating film adjacent to the element region. The above prevents the occurrence of overhanging structures which would otherwise partially block the source and drain implant and result in a high resistance region.