A Mott-Schottky-Constrained, Temperature-Unified Capacitance Model for SiC Schottky Barrier Diodes from 295 to 37 K

Abstract

Cryogenic circuit simulation requires capacitance models for silicon carbide (SiC) Schottky barrier diodes below 77 K. We present a temperature-unified depletion-capacitance model from C–V measurements over 37–295 K up to 25 V at 1 kHz. The conventional power law is retained, with zero-bias capacitance constrained by a normalized C–V-derived effective-density ratio N_CV(T) obtained from Mott-Schottky slopes. The same trend parameterizes the low-temperature built-in-potential and grading-coefficient variations. With the extracted N_CV(T) values, six globally fitted parameters reproduce all data with a relative root-mean-square error of 1.5%. At 37 K, N_CV = 0.562, consistent with partial freeze-out, and a room-temperature-only fit accordingly deviates by 26%.