Stress state of chromium nitride films deposited by reactive direct current planar magnetron sputtering

Abstract

Chromium nitride films were deposited on glass substrates using reactive dc planar magnetron sputtering. Film stress-state evaluation permitted a two-level classification into compressive and transition categories. Maximum stress levels in these compressive category films were in the (−) 0.83 to (−) 14.4 GPa range. Sputtering parameter weighting equations indicated the deposition parameters which influenced stress were sputtering pressure, sputtered flux incidence angle, film thickness, and the interactions between these parameters. Subsequent studies indicated substrate bias to be important in the −50 to −250 V interval. Thermal stresses contributed a compressive component of (−) 0.7 GPa which was approximately 4% of the peak compressive stress. Generally, deposition conditions promoting high normalized energies (energetic particle bombardment of the film) produced hard coatings which were highly stressed (compressive) with low resistivities.