Properties of radio frequency–sputtered alumina films on flat and grooved substrates

Abstract

Mechanical and chemical properties of rf-diode sputtered alumina films have been measured as a function of deposition conditions including substrate bias, bias phase, and sputter power. Similar films were deposited over grooved substrates, and the effect of the grooves on film microstructure and intrinsic stress was examined. Films deposited over nonplanar substrates show distinct regions in the vicinity of substrate steps where the material has a different microstructure, composition, stress, and chemical etch rate compared with material far from the steps. The elastic modulus and hardness of the material near the steps were measured by nanoindentation.