Silicon recess etch and epitaxial deposit for shallow trench isolation (sti)

Abstract

Some embodiments of the present disclosure relate to a method. In this method, a semiconductor substrate, which has an active region disposed in the semiconductor substrate, is received. A shallow trench isolation (STI) structure is formed to laterally surround the active region. An upper surface of the active region bounded by the STI structure is recessed to below an upper surface of the STI structure. The recessed upper surface extends continuously between inner sidewalls of the STI structure and leaves upper portions of the inner sidewalls of the STI structure exposed. A semiconductor layer is epitaxially grown on the recessed surface of the active region between the inner sidewalls of the STI structure. A gate dielectric is formed over the epitaxially-grown semiconductor layer. A conductive gate electrode is formed over the gate dielectric.