Compact Modeling of Temperature Effects in FDSOI and FinFET Devices Down to Cryogenic Temperatures

We present compact models that capture published cryogenic temperature effects on silicon carrier mobility and velocity saturation, as well as fully depleted silicon on insulator (FDSOI) and fin field effect transistor (Fin-FET) devices characteristics within the industry-standard Berkeley short-channel IGFET model (BSIM) framework for cryogenic IC applications such as quantum computing. For the core model charge density/surface potential calculation, we introduce an effective temperature formulation to capture the effects of the band tail states. We also present a compact model that corrects the low-temperature threshold voltage for the band-tail states, Fermi-Dirac statistics, and interface traps. New temperature-dependent mobility and velocity saturation models are accurate down to cryogenic temperature. In addition, we propose that experimentally observed ID dependence of subthreshold swing (SS) at cryogenic temperatures is a consequence of the expectedly higher rate of Coulomb scattering of free carriers.

Automated summary

The study presents compact models that capture the effects of silicon carrier mobility and velocity saturation at low temperatures, as well as corrects the characteristics of FDSOI and Fin-FET devices at low temperatures within the industry-standard BSIM framework. New temperature-dependent mobility and velocity saturation models are proposed to accurately model behavior down to cryogenic temperatures, with observed dependencies attributed to higher rates of Coulomb scattering.