The mechanism of phase transition induced by oxygen doping in zirconium nitride thin films

MO x N y (M represents transition metal) thin films have shown excellent performance in various fields such as temperature sensing, high-k gate dielectrics and decorative coatings. Thin film properties can be significantly affected by adjusting oxygen contents, while the physical mechanism of oxygen in MN x structure is not well explored. In this paper, the effects of oxygen doping in ZrN thin films (expressed as ZrO x N y ) on material modification and temperature sensing are discussed from a viewpoint of Zr vacancies (V Zr ). A phenomenon of phase transition from ZrN into Zr 3 N 4 structure is observed with increasing flow rates of N 2 /O 2 in thin film deposition. In addition, an electronic transition from metallic to semiconductor behavior is found even a slight oxygen is doped in ZrN structure. Based on the experimental results and first principal calculations, a physical model is proposed that V Zr can be induced in ZrN structure by oxygen doping. A small quantity of V Zr change the electronic behavior of the film from metallic to semiconductor type and a large quantity trigger phase transition from ZrN to Zr 3 N 4 structure. The results and model provide clear insights into engineering of ZrO x N y thin films for high performance temperature sensors. Graphical Abstract