A Quasi-3-D Scaling Length Model for Trapezoidal FinFET and Its Application to Subthreshold Behavior Analysis

Based on the equivalent channel width and equivalent number of gates, a quasi-3-D scaling length model for the trapezoidal FinFET (TzFinFET) is developed. By accounting for the coupling effects between equivalent double-gate FET and single-gate FET, the scaling length of TzFinFET can be accurately predicted. Besides Fin height, top Fin width, and gate oxide, the scaling length is also sensitive to the inclination angle induced by the process technology. By applying this derived scaling length to the TzFinFET, the subthreshold behavior model including threshold voltage and subthreshold swing can be achieved. Both threshold voltage roll-off and subthreshold swing roll-up can be well controlled by the scaling factor in accordance with the scaling theory. According to the scaling factor, the acceptable minimum channel length that allows the maximum subthreshold degradation can be uniquely determined. The variability of subthreshold characteristics with the process parameter is also taken into account in this paper.