Nitrogen-rich silicon nitride thin films for deep-ultraviolet Mirau interferometry

We report experimental results on W-transparent low-pressure chemical-vapor-deposition nitride thin films, We show that, by using nitrogen-rich rather than conventionally silicon-rich thin-film membranes, we are able to obtain more than 95% UV transparency below 250 am, while keeping the stress of the membrane manageable and below standard nitride's giga-Pascal stress. Using these results, we were able to microfabricate a UV Mirau interferometer for correlation microscopy. (C) 1997 Optical Society of America.