A physically based analytical model for the threshold voltage of strained-Si n-MOSFETs

A physically based analytic model for the threshold voltage Vt of long-channel strained-Si-Si1-(sub x)Ge(sub x) n-MOSFETs is given and confirmed with the help of numerical simulations for a wide range of channel doping concentration, gate-oxide thickness, and strained-Si layer thicknesses. The threshold voltage difference between strained- and unstrained-Si devices increases with channel doping but as such the increase is mitigated by gate oxide thickness reduction.