Modeling of the Subthreshold Swing in Cryogenic MOSFET With the Combination of Gaussian Band Tail and Gaussian Interface State

To quantitatively describe the inflection and the recently observed protrusion phenomenon in the subthreshold region at cryogenic temperature, this study presents a novel model featuring a Gaussian-distributed band tail, combining the Gaussian interface state positioned away from the energy band. The Gaussian band tail can capture the inflection phenomenon of low-temperature subthreshold swing (SS), and the introduction of the interface state in the forbidden band enables accurate modeling of the SS protrusion. The proposed model can favorably describe \textit{I}_{\text{DS}} - \textit{V}_{\text{GS}} , SS- \textit{I}_{\text{DS}} , and SS- T spanning from 10 to 300 K of the commercial 0.35- \mu m bulk n/p-MOSFET and 14-nm n-FinFET technology, potentially enabling a unified method of capturing the SS of a MOSFET at the cryogenic temperature.