All-analytic surface potential model for SOI MOSFETs

An all-analytic front surface potential model for SOI MOSFETs is presented, which is not only obtained from previously developed models, but is also derived from assumptions made for approximations of various operating regions. A single formula for the drain current is obtained by smoothly connecting the analytic solutions for various operating regions. The formula can be used from accumulation to strong inversion and from the partially depleted (PD) region to the fully depleted (FD) region. Owing to the one-dimensional nature of the model, the critical gate bias at which the transition occurs between the PD and FD regions can also be obtained analytically. Most secondary effects can easily be included in the current model and the model accurately reproduces numerical and experimental results. No discontinuity in the derivative of the surface potential is found and the newly introduced parameters used in the smoothing functions do not depend strongly on the process parameters.