Poisson-Schrödinger simulation of inversion charge in FDSOI MOSFET down to 0K - Towards compact modeling for cryo CMOS application

Abstract

Poisson-Schrodinger (PS) simulations and an analytical charge model for a back biased FDSOI structure operated at deep cryogenic temperatures have been developed. PS simulations has been conducted down to 0K, where metallic statistics applies, by replacing the F0 Fermi integral by a Heaviside function. Considering, as a first approximation, two separated channels for front and back interface, a set of analytical equations has been established based on a single subband scheme within the Airy approach, providing a good description of surface potential, inversion charge and capacitance characteristics of FDSOI structures operated at very low temperature and for various back biases and silicon thicknesses. This analytical charge model is a first step towards a compact model of FDSOI MOSFET for circuit design at cryogenic condition.