STRAIN RELEASE IN PFET REGIONS

摘要

A method for fabricating a semiconductor device, includes providing a strained silicon on insulator (SSOI) structure, the SSOI structure comprises, a dielectric layer(20) disposed on a substrate(10), a silicon germanium layer(30) disposed on the dielectric layer(20), and a strained semiconductor material layer(40) disposed directly on the silicon germanium layer(30), forming a plurality of fins(43, 45) on the SSOI structure, forming a gate structure(50) over a portion of at least one fin in a nFET region, forming a gate structure(60) over a portion of at least one fin in a pFET region, removing the gate structure(60) over the portion of the at least one fin in the pFET region, removing the silicon germanium layer(30) exposed by the removing, and forming a new gate structure(90) over the portion of the at least one fin in the pFET region, such that the new gate structure(90) surrounds the portion on all four sides．