Infrared interference coating by use of Si3N4 and SiO2 films with ion-assisted deposition

Silicon nitride (Si(3)N(4)) and silicon dioxide (SiO(2)) films were prepared by ion-assisted deposition, and a higher deposition rate was achieved for both films. The results of x-ray diffraction and transmission electron microscopy measurements showed that the films have amorphous structures. As measured by infrared (IR) spectrometry and x-ray photoelectron spectrometry, both stoichiometric films have extremely low hydrogen content. The IR optical constants of the films were determined by spectroscopic ellipsometry. Both films exhibited a low extinction coefficient at wavelengths from 2 to 7 microm. The application of Si(3)N(4) and SiO(2) films on the IR interference coating is demonstrated.