Patterning of ZnS–SiO2 by Laser Irradiation and Wet Etching

Generally, ZnS–SiO2 thin film is used as a protective layer in phase-change optical media. The wet etching characteristics of ZnS–SiO2 have been investigated, and it was found that ZnS–SiO2 can be patterned by laser irradiation and wet etching. Convex patterns of ZnS–SiO2 with steep taper profiles were formed. The minimum size of ZnS–SiO2 dots was 90 nm, and the minimum width of ZnS–SiO2 lines was 100 nm. These pattern sizes were approximately one-fourth of the laser beam spot from a 405 nm laser diode (LD) with an objective lens of 0.85 numerical aperture (NA). The pattern edges of ZnS–SiO2 dots and lines were clear and smooth. These results prove that ZnS–SiO2 is a useful material for forming nanometer-scale patterns.