Titanium nitride oxidation chemistry: An x-ray photoelectron spectroscopy study

TLDR

Previous studies reported TiN oxidation kinetics at 350–450 °C and identified an initiation time before rapid oxidation. This study investigates the oxidation of TiN. X‑ray photoelectron spectroscopy was employed to probe TiN oxidation mechanisms at 350 °C during the initiation period, and a thicker oxide sample was annealed in vacuum to 700 °C. Oxide thickness grows slowly over time, transitioning from amorphous to crystalline TiO₂, with intermediate TiO₂/TiN spectral features that suggest grain‑boundary oxidation, and after oxidation the capping oxide and intermediate material largely disappear from the analysis volume, implying oxygen and nitrogen dissolution into the bulk akin to nonevaporable getter activation.

Abstract

We report a study of the oxidation of TiN. In previous work, the oxidation kinetics for 350–450 °C were reported and an initiation time prior to fast oxidation was identified. In this study, x-ray photoelectron spectroscopy was used to investigate the oxidation mechanisms at 350 °C during this initiation time period. The oxide thickness increases slowly with oxidation time and the film appears to change from an amorphous TiO2 layer to a crystalline TiO2 layer. Spectral features which are intermediate between TiO2 and TiN are reported and a model involving grain boundary oxidation is proposed. One of the thicker oxides studied was annealed in vacuum to 700 °C. Following oxidation, some of the capping oxide and much of the intermediate material is no longer in the analysis volume and we suggest that the oxygen and nitrogen is being dissolved into the bulk in much the same way that nonevaporable getters are activated before use.