The effect of biaxial strain on the phonon-limited mobility in 4H-SiC MOSFETs

Abstract

We investigate the effect of biaxial tensile stress at the interface of 4H-SiC metal-oxide-semiconductor field effect-transistors on the phonon-limited mobility using theoretical calculations. The band structure under strain is obtained by the first-principles calculations, and the electronic states and potential of the inversion layer at the interface are determined by the Schrödinger–Poisson method. The mobility is calculated using the Fermi's golden rules. We find that the biaxial strain reduces the energy difference between the first and second conduction band minima. This leads to an increase in polar-optical phonon scattering, which becomes the dominant factor in the mobility degradation under the tensile strain.