Difference in electron mobility at 4H–SiC/SiO2 interfaces with various crystal faces originating from effective-field-dependent scattering

Abstract

Although the channel resistance is partially reduced by suppressing 4H–SiC/SiO2 interface trapping, interface scattering still presents a problem. To clearly extract the effective-field (Eeff) dependence of the dominant scattering, a body biasing technique was adopted, under the condition that the charge density is constant to fix the screening effect. The electron mobilities were observed to be several fold higher for a-, m-, and 03¯38¯ faces than for Si- and C-faces. This result is primarily due to a magnitude difference in the Eeff-dependent scattering; thus, the difference is emphasized at higher Eeff values. Physical parameters to reproduce the observed mobility were estimated by simulating Coulomb and roughness scattering.