Patent ID: 9410238
Filing Date: 2016-08-09
CPC Classification: C23C,G02B,Y10T

Claim Text:
1. A method comprising: a) providing a substrate comprising zinc sulfide or zinc selenide on a sputtering drum in a sputtering drum coating chamber; b) providing a source of alumina, a source of diatomic oxygen and a source of inert gas in the sputtering drum coating chamber, wherein a target distance of the source of alumina to the zinc sulfide or the zinc selenide ranges from 8 cm to 20 cm; c) rotating the substrate comprising the zinc sulfide or the zinc selenide on the sputtering drum at 0.75 to 3 revolutions per second; d) introducing diatomic oxygen in the sputtering drum coating chamber at a flow rate of 20 sccm to 80 sccm and introducing inert gas in the sputtering drum coating chamber at a flow rate of 30 sccm to 150 sccm at a total sputtering drum coating chamber pressure of 2×10 e) ionizing the diatomic oxygen and inert gas with microwaves at microwave powers of 1 kW to 5 kW and at a frequency of 1 GHz to 5 GHz; and f) depositing a layer of alumina 30 μm to 60 μm thick by pulsed DC magnetron sputtering or 30 μm to 100 μm thick by AC magnetron sputtering on the zinc sulfide or zinc selenide at a deposition rate of 60 Å/minute to 270 Å/minute at pulsed power ranges of 3 kW to 9 kW and frequency ranges of 20 kHz to 50 kHz, wherein the zinc sulfide or zinc selenide are maintained at temperatures of 40° C. to 200° C.