PIEZORESISTIVE SIMULATION IN MOSFETS

The piezoresistivity effects in MOSFET devices have been experimentall y determined. The PI11, PI12 and PI44 2D piezoresistive coefficients i n both n- and p-type inversion layers have been analytically developed including the quantum effects, the intravalley-intervalley scattering effects, the different saturation velocity effects and the hot-electr on effects. In addition, the hole stress-induced effective-mass modifi cation has been applied to determine the piezoresistive coefficients i n p-type inversion layers. The carrier population variation due to the change of the band gap has also been taken into account in the weak i nversion regime. A mixed 2D/3D model for the piezoresistivity effects has been introduced in the process/device simulator IMPACT and a good agreement between simulation and experiment has been achieved.