A self-consistent analytic threshold voltage model for thin SOI n-channel MOSFETs

An accurate analytical threshold voltage model is presented for fully-depleted SOI n-channel MOSFETs having a metal-insulator-semiconductor-insulator-metal structure. The threshold voltage is defined as the gate voltage at which the second derivative of the inversion charge with respect to the gate voltage is maximum. Since the inversion charge is proportional to the drain current at low bias, the model is self-consistent with the measurement scheme when the threshold voltage is measured as the gate voltage at which the variation of the transconductance at low drain bias is maximum. Numerical simulations show good agreement with the model with less than 3% error.