Hysteresis-free deposition of TiOxNy thin films: Effect of the reactive gas mixture and oxidation of the TiN layers on process control

This paper investigates the effect of the reactive gas mixture (N2 + O2 + Ar) and oxidation of the nitride layers on the system stability during the reactive sputter deposition of TiOxNy thin films. The present research is an extension of previous investigations conducted by Severin et al. (Appl. Phys. Lett., 88 (2006) 161504) and Duarte et al. (Appl. Surf. Sci., 269 (2013) 55-59) in which the Berg's model was used to study reactive deposition of oxynitrides. The results show that the addition of N2 to the process avoids the formation of a hysteresis loop and facilitates the deposition of films with fractions of TiO2 at any value. These achievements are not possible without this procedure. In contrast, despite eliminating plasma instabilities, the addition of N2 decreases the mass deposition rate due to the modifications in the sputtering yield. Other results show that the oxidation of TiN also plays a key role in the mass deposition rate and in the hysteresis loop.