Intrinsic origin of electron scattering at 4H-SiC(0001)/SiO₂

We introduce a first-principles study to clarify the carrier-scattering property at the SiC/SiO$_2$. Interestingly, the electron transport at the conduction-band edge is significantly affected by the introduction of oxygen, even though there are no electrically active defects. The origin of the large scattering is explained by the behavior of the internal-space states (ISSs). Moreover, the effect of the ISSs is larger than that of the electrically active carbon-related defects. This result indicates that an additional scattering not considered in a conventional Si/SiO$_2$ occurs at the SiC/SiO$_2$.