Co-development of stress and texture in reactive magnetron sputtered TiN films revealed by in situ film stress measurements

Titanium nitride (TiN) films up to 100 nm thickness were deposited by reactive magnetron sputter deposition on silicon substrates while measuring the film force in situ. The energy per deposited atom supplied to the growing film by ion bombardment was varied in two ways: a) by changing the deposition pressure and b) by changing the bias voltage applied to the substrate. Both variations affected the film force, the microstructure and the film texture. More energetic deposition conditions led to a continuous build up of stress, a dense microstructure and a 001 film texture almost independent of film thickness. These findings lead us to conclude that a 001 film texture is more susceptible to stress generation by an ion bombardment than a 111 film texture. Further, from the similar effect of a pressure increase and a bias voltage decrease on the film growth and characteristics we identify ion–neutral charge transfer collisions in the substrate sheath as the mechanism by which the deposition pressure influences film characteristics.