Benchmarking of the BSIM-BULK for Cryo-CMOS Design

This article presents a benchmarking study of compact models at cryogenic temperatures, employing BSIM-BULK as the core model. The BSIM-BULK model is validated with characterized data across multiple temperatures, showing a strong correlation with the experimental terminal characteristics. The robustness and qualitative accuracy of the model are assessed through a series of benchmark tests. The Gummel symmetry test is utilized for symmetry analysis, confirming the symmetry of the drain current and the continuity of its derivatives, down to cryogenic temperatures. The nonlinear behavior of the model is evaluated through harmonic balance tests, with slopes at each temperature aligning well with expected physical trends. Furthermore, we have applied tree-top and slope ratio tests to evaluate the smooth transition of the model from weak to strong inversion, demonstrating consistent and smooth behavior in all regions of MOSFET operation at all temperatures.