Abstract: The ratio of silane-to-ammonia in a reaction designed to deposit a silicon nitride thin film affects the refractive index as well as the absorption coefficient of the film. By controlling the influx of these gases such that an essentially small ratio of silane-to-ammonia exists in a reaction chamber, a silicon nitride film 9 is deposited which is transparent to ultraviolet radiation 4. The exact ratio needed is dependent upon the geometry and operating parameters of the reaction chamber system employed in the deposition process. Ultraviolet light transparent silicon nitride film provides a superior passivation layer 9 for erasable programmable read only memory integrated devices 2.