Modeling of SiC(0001) n-Channel MOSFETs Based on Comprehensive Understanding of Electron Scattering Mechanism

In this study, we systematically analyzed the electron scattering mechanism in 4H-SiC(0001) MOS channels and developed a physics-based model for SiC n-channel MOSFETs. Free electron mobilities (${{{\mu }}\mathrm {_{free}}}$) in SiC MOSFETs with different p-body doping concentrations (${N}\mathrm{_{A}}$=${\mathrm {\text {3} \times \text {10}^{\text {15}}}}$–${\mathrm {\text {3} \times \text {10}^{\text {18}} \ \text {cm}^{-\text {3}}}}$) were determined by MOS-Hall effect measurements in the temperature range of 200–400 K. Theoretical calculation of${{{\mu }}\mathrm {_{free}}}$was conducted using our originally developed model, which accounts for the impact of a high density of electrons trapped in the SiC subsurface region. The model successfully reproduced the experimental Hall mobilities across a wide range of effective normal field and temperature. It was found that the fixed charge density near the SiC/SiO${\mathrm {_{2}}}$interface increases with increasing${{{N}}\mathrm {_{\text {A}}}}$. In addition, we have demonstrated that${{{\mu }}\mathrm {_{free}}}$is mainly limited by Coulomb scattering due to a high density of fixed charges at the MOS interface as well as surface roughness scattering. Based on these understandings, our model successfully reproduced the experimental gate characteristics of MOSFETs with different${{{N}}\mathrm {_{\text {A}}}}$of p-body in the temperature range of 200–400 K.