Effect of CHF3/Ar Gas Flow Ratio on Self-masking Subwavelength Structures Prepared on Fused Silica Surface

Based on an advanced technology, randomly-aligned subwavelength structures (SWSs) were obtained by a metal-nanodot-induced one-step self-masking reactive-ion-etching process on a fused silica surface. Metal-fluoride (mainly ferrous-fluoride) nanodots induce and gather stable fluorocarbon polymer etching inhibitors in the reactive-ion-etching polymers as masks. Metal fluoride (mainly ferrous fluoride) is produced by the sputtering of argon plasma and the ion-enhanced chemical reaction of metal atoms. With an increase in CHF3/Ar gas flow ratio, the average height of the SWSs increases, the number of SWSs per specific area increases and then decreases, and the optical transmittance of visible light increases and then decreases. The optimum CHF3/Ar gas flow ratio for preparing SWSs is 1:5.