Analytical threshold voltage and subthreshold swing model for TMG FinFET

Abstract

ABSTRACTAn analytical modelling of the subthreshold surface potential, threshold voltage (VT) and subthreshold swing (SS) for a triple material gate (TMG) FinFET is presented. The basis of the 3D solution is two separate 2D solutions. The FinFET is separated into two 2D structures: asymmetric triple material double gate (TMDG) and symmetric TMDG MOSFETs. Their potential distributions are obtained by solving the corresponding 2D Poisson’s equations. The potential distribution in TMG FinFET is obtained by a parameter-weighted sum of the two 2D solutions. Utilising the concept of minimum source barrier as the leakiest channel path, the minimum value of the surface potential is developed from the potential model. This leads to the derivations for the threshold voltage and SS. Furthermore, the effects of variation in gate work function and gate length are investigated for analytically developed SS and VT models. Our models are validated against TCAD Sentaurus-simulated results and found to be quite accurate.