Abstract

The effects of ultrasound-assisted deposition (UAD) of ZrO₂, Ta₂O₅, and MgF₂ films on their optical and structural properties have been investigated. The glass or fused silica substrates (with areas ~25 cm²) are attached with Torr-Seal to tubular piezoelectric transducers, which are, in turn, clamped to stationary tooling within a Balzers 510 evaporation plant. The transducers are driven by an ENI 2100L rf power amplifier with a 10-kHz to 12-MHz bandwidth and a power output of around 150 W. Radiative heating of the substrates, with and without ultrasound, was also performed to distinguish between purely thermal and ultrasonic effects. Results thus far indicate that ultrasonic powers above 100 W are required to induce detectable changes in UV absorption and vacuum-to-air shifts of the spectral profile. At substrate temperatures (T_s) near ambient, UV absorption in UAD films is equal to or slightly higher than in conventionally deposited (CD) films. For T_s above 100°C, UV absorption tends to increase for UAD vs CD films; baking tends to lower the absorption, indicating that UAD films are oxygen deficient. No changes in crystal structures at high T_s as measured by x-ray diffraction, in surface roughness as observed with Nomarski microscopy, and in robustness as determined by controlled exposure to high temperatures and humidities, were noted.

© 1986 Optical Society of America