Two methods to improve the optical quality of Ni-C multilayer coatings: ion bombardment and optimization of the substrate temperature

We report on two methods for producing multilayer optics with considerably better reflectivities than `state of the art' coatings: deposition at optimized substrate temperatures and application of ion beam bombardment. In the first case we show that deposition of Ni - C multilayer coatings at optimized substrate temperatures results in increases in reflectivity at (lambda) equals 6.76 nm with a factor of 1.4 (Toptimum approximately equals 100 degree(s)C, d approximately equals 5.0 nm) compared to those deposited at room temperature. In the case of ion bombardment (at room temperature) the increase in reflectivity is more dramatic: a factor of 4 was observed for ion etched Ni - C coatings compared to nontreated ones (ion beam of 200 eV Ar+ at an angle of incidence of 45 degree(s), d approximately equals 2.8 nm). We note that due to the difference in d-spacing of the coatings the increases can not be compared directly. Finally, we discuss thermal treatment of Ni - Si multilayer coatings: contrary to Ni - C we observed an increase in reflectivity at temperatures below room temperature.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.