Comparative analysis of basic transport properties in the inversion layer of bulk and SOI MOSFETs: a Monte-Carlo study

A Monte-Carlo simulator for the quasi-2D electron gas in the inversion layer of bulk and SOI MOSFETs has been developed. The code has been used to validate the momentum-relaxation-time technique, commonly used to evaluate the low field mobility, pointing out the importance of inter-subband transitions in SOI devices. The high field transport properties in thin SOI MOSFETs have been investigated, showing for the first time that surface roughness scattering could have a strong impact on the saturation velocity whose value is significantly lower than the value reported for bulk silicon and bulk MOSFETs. On the other hand, the high energy carrier distribution is only weakly influenced by carrier quantization.