Charge balance semiconductor devices with increased mobility structures

Abstract

Charge balanced semiconductor devices with increased mobility structures and methods for making and using such devices are described. The semiconductor devices contain a substrate heavily doped with a dopant of a first conductivity type, a strained region containing a strain dopant in an upper portion of the substrate, an epitaxial layer being lightly doped with a dopant of a first or second conductivity type on the strained region, a trench formed in the epitaxial layer with the trench containing a MOSFET structure having a drift region overlapping the strained region, a source layer contacting an upper surface of the epitaxial layer and an upper surface of the MOSFET structure, and a drain contacting a bottom portion of the substrate. Since the drift region of the MOSFET structure is formed from the strained region in the substrate, the mobility of the drift region is improved and allows higher current capacity for the trench MOSFET devices. Other embodiments are described.