Abstract: Apparatus for producing a wet oxygen stream for a semiconductor furnace to form oxide layers on silicon wafers. A quartz vessel with quartz chips is heated to 450° C. and a mixture of water and oxygen is introduced at the bottom of the vessel. Vaporization occurs at the input of the water and oxygen into the vessel. The output of wet oxygen as superheated stream passes through the chips and is taken from the top of the vessel to the furnace. The quartz vessel is nested in an aluminum body containing heaters to maintain constant temperature. The ratio of water vapor to oxygen in the wet stream is constant to produce layers of predictable characteristics.