Assessment of the Application of the Sputtering Process to Beryllium for Hardening Optical Coatings

摘要

Two principal deposition processes are compared for the case of depositing 1 to 2 mu m beryllium on fused-silica substrates. While the evaporation-deposition process offers advantages such as higher deposition rate, purification of the evaporant and efficient use of masks, the sputter-deposition is more versatile, and therefore more effective, in varying and controlling the microstructure of the deposits. The versatility comes about because the latter process has five major operational parameters to be selected or adjusted. Consequently, sputter-deposited beryllium films are expected to display more desirable microstructures and better surface finish than evaporation-deposited films. (ERA citation 11:016638)