Authors: J. He, Y. Song, X. Niu, G. Zhang, X. Zhang, R. Huang, M. Chan and Y. Wang
Affilation: Peking university, China
Pages: 616 - 621
Keywords: MOSFET, compact modeling, device physics, surface potential based model, charge-sheet approximation, benchmark test
This paper reports the benchmark test results of surface potential solution, inversion charge and channel current calculation, and short-channel effect model of various surface based charge-sheet models and our PUNSIM development to breakthrough the drawbacks of the present surface potential based models. Compared with the Pao-Sah model, most charge-sheet models produce certain degree difference in different operation regions. In some cases the simplified approximations even result in an incorrect trend in the inversion charge prediction. In order to model the channel current, a semi-empirical channel current equation in the surface potential based charge-sheet models cannot be avoided and this leads to inconsistency between the channel current and channel charge, and some channel current errors. The present surface potential based models such as SP and HISIM used so-called lateral gradient factor to model all short-channeled effects. TI and Philip’s evaluation on HISIM and PSP verified their difficulty in fitting the sub-threshold region of short-channel devices. Our PUNSIM is developed to overcome mainly drawbacks of the presented surface potential based models and aiming at fulfilling the features: physics based analytic solution of the surface potential equation; Accurate description of inversion charge; Physics based channel current equation and calculation; Self-consistently modelling of short-channel effects.