Origin of hydrogen passivation in 4H -SiC

Abstract

Carbon vacancy ${\mathrm{V}}_{\mathrm{C}}$ is the dominant detrimental defect in SiC, and hydrogen passivation of ${\mathrm{V}}_{\mathrm{C}}$ is often used to facilitate its application in electronic devices. However, the exact nature of hydrogen passivation of ${\mathrm{V}}_{\mathrm{C}}$ in $4H$-SiC remains inconclusive in view of the available divergent experiment and theoretical findings. Here, using the Heyd-Scuseria-Ernzerhof screened hybrid density functional calculations, we demonstrate that the ${\mathrm{V}}_{\mathrm{C}}$ defect can capture up to four hydrogens, and the electrically active levels within the band gap can be entirely passivated, in line with recent reported experimental observations. This paper, thus, casts light on the role of hydrogen passivation in SiC.