Electron-scattering mechanisms in heavily doped silicon carbide MOSFET inversion layers

Hall-effect measurements of n-channel MOS devices were used to determine the main scattering mechanisms limiting mobility in SiC MOSFETs. MOS-gated Hall characterization, which was performed as a function of gate bias and body bias, indicates that surface-roughness scattering and Coulomb scattering are the main scattering mechanisms limiting electron mobility in SiC MOSFETs at room temperature. A charge-sheet model, including incomplete ionization and Fermi-Dirac statistics, is used to calculate the surface electric fields in order to develop an expression for surface-roughness scattering. In the samples used for this paper, at electron sheet densities less than 1.8 x 10(12) cm(-2), Coulomb scattering dominates, while surface roughness is dominant at higher sheet densities.