Abstract

Deposition of dielectric coatings by reactive sputtering is widely used in the microelectronic industry. The application of the process for the deposition of optical coatings has been very limited. In this report we outline results in our effort to apply the sputtering process for dielectric coatings. Coatings with excellent optical properties of SiO₂, Al₂O₃, HfO₂ and TiO₂, were deposited using magnetron sputtering of Si, Al, Hf, and Ti, respectively with oxygen backfill. These materials cover a wide range of indices from 1.45 to 2.5. Coatings were deposited in a 60 cm box coater. The deposition system is equipped with a three inch diameter magnetron sputtering source. The system is cryogenically pumped to a base pressure of 3 × 10^–7 Torr. The pressure with oxygen backfill is 5 × 10^–4 Torr, while the total pressure after adding the argon is 1 × 10^–3 Torr. The optical and mechanical properties of single and multilayer coatings were examined. The index of refraction of SiO₂, Al₂O₃, and TiO₂ were 1.45, 1.64, 2.0, and 2.5, respectively. Coatings were durable with good adhesion and abrasion resistance.

© 1990 Optical Society of America