High-Performance nMOSFETs Using a Novel Strained Si/SiGe CMOS Architecture

摘要

Performance enhancements of up to 170% in drain current, maximum transconductance, and field-effect mobility are presented for nMOSFETs fabricated with strained-Si channels compared with identically processed bulk Si MOSFETs. A novel layer structure comprising Si/Si0 7Ge0 3 on an Si0 85Ge0 15 virtual substrate (VS) offers improved performance advantages and a strain-compensated structure. A high thermal budget process produces devices having excellent on/off-state drain-current characteristics, transconductance, and subthreshold characteristics. The virtual substrate does not require chemical-mechanical polishing and the same performance enhancement is achieved with and without a titanium salicide process. Index Terms—CMOS, drain-current enhancement, nMOSFETs, self-heating, SiGe, strained silicon, thermal budget, transconductance enhancement, virtual substrate.