Optical device improvement

A method of processing an optical device comprising:

• positioning the optical device on a substrate support in an interior volume of a process chamber, the optical device comprising an optical device substrate and a plurality of optical device structures formed over the optical device substrate and spaced apart from each other, each optical device structure including a bulk region formed of silicon carbide and one or more surface regions formed of silicon oxycarbide;
• providing one or more process gases to the interior volume of the process chamber;
• heating the interior volume of the process chamber to a temperature of at least 600° C. for a first time period when the optical device is on the substrate support;
• and
• stopping the heat after the first time period, wherein a carbon content of the one or more surface regions of each optical device structure is reduced by at least 50% compared to the carbon content of the one or more surface regions of each optical device structure before the first time period.

A method of processing an optical device comprising:

• positioning the optical device on a substrate support in an interior volume of a process chamber, the optical device comprising an optical device substrate and a plurality of optical device structures formed over the optical device substrate and spaced apart from each other, each optical device structure including a bulk region formed of silicon carbide and one or more surface regions formed of silicon oxycarbide, wherein the optical device substrate is formed of silicon carbide and the plurality of optical device structures are gratings configured for use in a waveguide combiner;
• providing one or more process gases including hydrogen to the interior volume of the process chamber;
• exposing the optical device to a plasma generated from the one or more process gases for a first time period when the optical device is on the substrate support;
• and
• stopping the plasma after the first time period, wherein a carbon content of the one or more surface regions of each optical device structure is reduced by at least 80% compared to the carbon content of the one or more surface regions of each optical device structure before the first time period.