A new two-dimensional threshold voltage model for cylindrical, fully-depleted, surrounding-gate (SG) MOSFETs

Based on two-dimensional (2D) Poisson potential solution, a compact, analytical model for threshold voltage in cylindrical, fully-depleted, surrounding-gate (SG) MOSFETs is successfully derived. The minimum surface potential ϕmin,surface is used to develop the threshold voltage model. Besides decreasing the characteristic factor, both the thin silicon body and gate oxide can reduce the threshold voltage roll-off simultaneously. It is also found that the threshold voltage shift is dependent on the scaling factor of λ1L. The high scaling factor is preferred to alleviate threshold voltage degradation.