Improved Electronic Performance of HfO₂/ SiO₂ Stacking Gate Dielectric on 4H SiC

The MOS characteristics of an atomic layer-depositedHfO₂/ N₂O-nitridedSiO₂stacking gate dielectric on n-type 4H SiC (0001) has been investigated. Three different thicknesses of nitridedSiO₂(2, 4, and 6 nm) have been sandwiched betweenHfO₂and SiC. The electronic performance of the stacking dielectric depends on the thickness of the nitridedSiO₂. Among the stacking dielectrics, the lowest effective oxide charge and interface-trap density as well as the most reliable dielectric has been demonstrated by a sample with the thickest nitridedSiO₂. The reason for this observation is proposed.