The RASIRC Steamer '01 Series
The RASIRC Steamer combines a clean steam generator and steam purification assembly into a single system. All wetted components in the liquid path are quartz or Teflon®. The purified steam path components are quartz and Teflon® fittings and valves. The RASIRC Steamer is proven to increase oxide growth rate, chamber uniformity, film quality, and/or reduce operating cost when compared against all other steam technologies.
Users of the RASIRC Steamer demonstrated increased growth rate and uniformity by elimination of the oxygen carrier gas.
The growth rate of the oxide layer is directly related to the effective diffusion coefficient of the water molecules into the oxide layer and the equilibrium concentration in the immediate area. When a carrier gas is used to deliver water vapor, the carrier gas molecules generate a partial pressure. This partial pressure lowers the partial pressure of water vapor and slows the diffusion of water into the oxide film. The result is lower driving force and slower growth rate.
 Recent tests show reduction of 67 different metals to below detectable limits. Some contaminants have been verified to less than 0.0005 parts per billion. Urea, Nitrogen and CO2 can also be eliminated. Because the RASIRC Steamer works with water vapor at low pressures, stainless steel delivery systems can be replaced with quartz and fluoropolymer piping systems.
The RASIRC Steamer compensates for the partial pressure created by the carrier gas by delivery of ultrapure steam at a constant positive pressure. By eliminating the carrier gas and blanketing the entire furnace tube in pure water vapor, even the loading end of the furnace tube reaches maximum theoretical growth rate.
RASIRC Steamer uses a non-porous hydrophilic membrane that selectively allows water vapor to pass. Selectivity is significant with up to 1,000,000x relative to nitrogen molecules. In the vapor phase, the membrane only allows water. All other molecules are greatly restricted, so contaminants in water such as dissolved gases, ions, TOCs, particles, viruses, bacteria, pyrons, and metals can be removed n the steam phase.
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