High Quality Content by WIKIPEDIA articles! Ultra-high-purity steam, also called clean steam, UHP steam or high purity water vapor, is used in a variety of industrial manufacturing processes that require oxidation or annealing. These processes include oxide layers grow on silicon wafers for the semiconductor industry and for passivation layers used to improve the light capture ability of crystalline photovoltaic cells. Several methods and technologies can be employed to generate ultra high purity steam, including pyrolysis, bubbling, direct liquid injection and purified steam generation. The level of purity, or the relative lack of contamination, affects the quality of the oxide layer or annealed surface. The method of delivery affects growth rate, uniformity and electrical performance. Oxidation and annealing are common steps in the manufacture of such devices as microelectronics and solar cells.