Effects of plasma immersion ion nitridation on dielectric properties of HfO2

Plasma immersion ion nitridation is used to produce thin HfO2 films with improved thermal and electrical properties. The film composition is investigated by examining the chemical shifts of the Hf 4f, Si 2p, and N 1s core-level spectra using x-ray photoelectron spectroscopy. The improved thermal stability and interfacial microstructure are further confirmed by high-resolution cross-sectional transmission electron microscopy. Electrical studies show an equivalent oxide thickness of about 1.25nm, a negligible hysteresis of about 5mV, and a low fixed charge density.