Low-temperature ion beam sputtered optical coatings

In thin film deposition processes, the lower limit of the deposition temperature is determined by the used coating technology and the duration of the coating process and is usually higher than room temperature. Hence, the processing of thermally sensitive materials and the adjustability of thin film morphology are limited. In consequence, for factual low-temperature deposition processes, an active cooling of the substrate is required. The effect of low substrate temperature on thin film properties during ion beam sputtering was investigated. The SiO2 and Ta2O5 films grown at 0◦C show a trend of lower optical losses and higher laser induced damage threshold (LIDT) compared to 100◦C.