Abstract

The optical properties of spin-coated solgel derived Ta₂O₅ films for potential application as near UV antireflective coatings on high index substrates are presented. As an illustrative example experimental results are discussed of an AR coating on a silicon substrate optimized for 370 nm. The coating parameters are adjusted by controlling the acid catalyzed hydrolysis of Ta(OC₂H₅)₅, the spin coating parameters, and heat-treatment processing. Film thickness uniformity measured across the wafer was better than 1%, and all the coatings tested passed the standard scotch-tape test before and after heat treatment and exhibited no change in optical properties after submersion in liquid N₂. Films subjected to rapid thermal processing at temperatures ranging from 300 to 1000°C reduced the reflectance loss in some cases by as much as 95%.

© 1989 Optical Society of America