Effective Normal Field Dependence of Inversion Channel Mobility in 4H-SiC MOSFETs on the (1120) Face

摘要

The dependence of effective channel mobility (μ_(eff)) in inversion layer of 4H-SiC MOSFETs on (1120) face with a wide range of substrate impurity concentrations (10~(15) to 10~(17) cm~(-3)) on the effective normal field (E_(eff)) has been investigated. The maximum value of the μ_(eff) decreases with the increase in the substrate impurity concentration while the μ_(eff) tends to converge into a unique curve in higher E_(eff) region independent of the substrate impurity concentration. The measurement temperature dependence of the μ_(eff) indicates that the μ_(eff) is predominately governed by phonon scattering mechanism. It is also shown that the μ_(eff) is improved due to the gate oxidation at lower temperatures, suggesting the affect of the interface states at SiO_2/SiC interface.