Stability and band offsets of nitrogenated high-dielectric-constant gate oxides

We find that addition of nitrogen to high-dielectric-constant gate oxides such as HfO₂, La₂O₃, and silicates adds gap states up to 1.2 eV above their valence-band edge. This reduces the valence-band offset, but not by enough to reduce the hole injection barrier to unsafe levels. Nitrogen also leads to a decrease in average atomic coordination, which may help to increase their resistance to crystallization and ability to withstand high temperature processing.