Investigation on Channel Mobility of SiC Trench MOSFET

Abstract:
This paper introduces a novel mobility extraction structure for accurate characterization of intrinsic channel behavior in silicon carbide (SiC) trench metal-oxide-semiconductor field-effect transistor (MOSFET). The individual contributions of phonon scattering, surface roughness scattering, and coulomb scattering to channel mobility are quantitatively analyzed. Experimental results reveal that coulomb scattering dominates mobility degradation below 200deg C when the root-mean-square (RMS) trench sidewall surface roughness remains below 0.4 nm. To mitigate coulomb scattering, a three-step optimization approach is implemented: (1) gate oxide interface trap reduction, (2) SiC interface lattice damage repair, and (3) inversion layer defect suppression. These measures collectively increase peak field mobility by 42.9%, 50.3 cm²V^-1s^-1 to 71.9 cm²V^-1s^-1.