Abstract: In a photo-CVD system, ultraviolet light is introduced into a reaction chamber from light emitting elements of ultraviolet light sources, through transparent bulb surfaces thereof, and through elongated light pipes in a sealed wall bounding the reaction chamber. This prevents molecules of reactant gas in the reaction chamber from reaching and being deposited on the transparent bulb surfaces, and thereby prevents buildup of such reactant molecules from occurring and impeding flow of ultraviolet light into the reaction chamber.

Abstract: A photo-assisted chemical vapor deposition system includes a reaction chamber, a susceptor in the reaction chamber supporting a wafer, a source for introducing reactant gas into the reaction chamber through an inlet port, and a cover positioned in sealed relationship to the housing and partially bounding the reaction chamber, the cover including a plurality of elongated light pipe openings each having a length comparable to the thickness of a boundary layer of the reactant gas and a diameter-to-length ratio small enough to maintain one-dimensional purge gas flow through the light pipe openings. A plurality of transparent windows are disposed in sealed relationship with the cover and bound an outer end of each of the light pipe openings. Ultraviolet light is introduced through the light pipe openings, which also provide a thick gas layer through which reactant species of the reactant gas must diffuse to reach the window surface.