Subthreshold Behavior Models for Nanoscale Short-Channel Junctionless Cylindrical Surrounding-Gate MOSFETs

With the exact solution of the 2-D Poisson's equation in cylindrical coordinates, analytical subthreshold behavior models for junctionless cylindrical surrounding-gate (JLCSG) MOSFETs are developed. Using these analytical models, subthreshold characteristics of JLCSG MOSFETs are investigated in terms of channel electrostatic potential distribution, subthreshold current, and subthreshold slope (SS). It is shown that the electrostatic potential distribution, subthreshold current, and SS predicted by the analytical models are in close agreement with 3-D numerical simulation results without the need of any fitting parameters. These analytical models not only provide useful physical insight into the subthreshold behaviors, but also offer basic design guideline for the nanoscale JLCSG MOSFETs.