Field dependence of the electron drift velocity along the hexagonal axis of 4$H$-SiC

The forward current–voltage characteristics of mesa-epitaxial 4$H$-SiC Schottky diodes are measured in high electric fields (up to 4 $\times$ 10$^5$ V/cm) in the $n$-type base region. A semi-empirical formula for the field dependence of the electron drift velocity in 4$H$-SiC along the hexagonal axis of the crystal is derived. It is shown that the saturated drift velocity is (1.55 $\pm$ 0.05) $\times$ 10$^7$ cm/s in electric fields higher than 2 $\times$ 10$^5$ V/cm.