Physics-Based Compact Model Extension of MOSFET Capacitance Down to Deep-Cryogenic Temperature Ranges

This work presents an extension of the BSIM-BULK compact model capacitance part to include physics-based descriptions of temperature-dependent effects down to cryogenic regimes. Key enhancements address phenomena such as carrier freeze-out, field-assisted ionization and temperature dependency of the flat-band voltage. Robust solutions to numerical convergence challenges from extremely small floating-point numbers are implemented. The extended model demonstrates improved accuracy in capturing the temperature dependence of both lowvoltage MOSFET and high-voltage LDMOS capacitance over a wide operating range, validated against experimental data.