A Comparison Study of Velocity Saturation Models for Gate-all-around MOSFETs

In this paper, a comparison study between different drain current models including velocity saturation effect for gate-all-around (GAA) MOSFET is performed from the aspect of accuracy and symmetry. A charge-based drain current model with velocity saturation effects by the Caughey- Thomas model with an exponent factor n=2 is developed. Its relationships with the industry standard BSIM-CMG model which assumes an exponent factor n=1 are discussed. 3-D TCAD simulations are performed to benchmark the models' accuracy. It is shown that similar accuracy is achieved with both models while applying an even number in the velocity saturation formula helps improving the model's performance under Gummel symmetry tests.