Dynamic stress investigations for cubic boron nitride films deposited by triode sputtering technique

In the present work c-BN films have been deposited on unheated silicon substrates by the triode sputtering technique. The films were characterized by infrared spectroscopy. High-resolution cross-sectional TEM is used to confirm the FTIR results. Films with c-BN content up to 70% were obtained at temperature of 300°C in a pure nitrogen discharge. The addition of argon in the discharge increases the c-BN content up to 90%. It is well known that the development of intrinsic stress hinders the deposition of thick c-BN films and consequently limits their applications. In order to understand the behavior of the stress within the film better, we have recorded infrared spectra and substrate curvature after various deposition times, with the same experimental conditions. The results give the dynamic stress profile during deposition and, therefore, enable a better understanding of the behavior of the stress and its relationship to the transition from the hexagonal phase to the cubic one. Therefore, the deposition conditions have been changed during film growth, in order to reduce the stress level and to try to improve the adhesion.