Abstract

AIN material is well known with its high band gap, electroinsulating and piezoelectric properties, chemical stability, hardness and high decompoition temperature [1]. AIN thin films find large application in microelectronics and optoelectronics. They are good thermal conductors and resistant to thermal shocks [2], So far they do not find large application in optical coatings due to the technological difficulties in their production and large compressive stress. The films are subjected to oxidizing during heating under ambient air, which leads to reducing their refractive index and change of their mechanical and other physical properties [3], Additional big problem so far is the higher extinction coefficient of AIN, which normally exceeds 10^-3 and make it unacceptable for many optical applications. Nevertheless, AIN is a prospective material for deposition of multilayer stacks of type Al₂O₃/AlN or index profile coatings from evaporation or sputtering of metal Al and alternative changing the reactive gases in the vacuum chamber. Deposition of AIN thin films with high refraction index, low extinction coefficient and small mechanical stress still seems a challenging task.

© 1998 Optical Society of America