Analytical modelling and temperature dependence of threshold voltage in short channel fully depledted cylindrical gate MOSFET

Abstract

A novel physics-based analytical model for short-channel effects in thin film fully depleted cylindrical gate MOSFET has been presented in this thesis. The scaling parameter was derived from the cylindrical form of Poisson's equation by assuming a parabolic potential in the radial direction. Analytical expressions for natural length, Ii, threshold voltage, Vth, threshold voltage shift, LlVth, sub-threshold swing, S, and drain-induced barrier lowering, DIEL, were derived for the cylindrical gate MOSFET and their response to the variation in parameters like gate length, silicon film thickness, drain voltage, etc. have been carefully studied. The results obtained from these analyses were compared to those of the double gate silicon-on-insulator MOSFETs (DG-SOI MOSFETs). The cylindrical gate MOSFET exhibits better short-channel effect immunity compared to the DG-SOI MOSFETs. Finally, an analytical temperature dependent model for threshold voltage in thin film fully depleted cylindrical gate MOSFET has also been developed using a Gaussian doping profile and is compared with that of the DG-SOI MOSFETs.