Abstract—Variability improvement of metal-oxidesemiconductor field-effect transistors (MOSFETs) characteristics with high-k HfON gate insulator by Si surface flattening was investigated. The Si surface flattening process was carried out by Ar/4.9%H2 anneal utilizing rapid thermal annealing system. The HfON gate insulator was formed by the in-situ Ar/O2 plasma oxidation of HfN utilizing elect…