A subthreshold swing model for FD SOI MOSFET with vertical Gaussian profile

Fully-depleted (FD) silicon-on-insulator (SOI) MOSFETs have attracted considerable attention due to their superior short-channel immunity and ideal subthreshold characteristics. With the size of device scaling down, the subthreshold operation has become an important area in integrated circuits design nowadays. A number of theoretical models accounting for the subthreshold characteristics of SOI MOSFETs have been developed [1-2]. For deep sub-micron SOI MOSFETs, device characteristics will be significantly affected by the doping concentration. It may well be that the transistor channel doping profile becomes closer to Gaussian profile in nature due to many ion implantation stages required during the fabrication process [3-6]. In this work, an analytical subthreshold swing model is developed for FD SOI MOSFETs with vertical Gaussian profile based on the analytical solving of the two-dimensional Poisson's equations.