Abstract: Apparatus and method for generating steam free of silica-containing droplets. The apparatus makes use of the fractional distillation properties of water/quartz mixtures. At the moderately high pressures and corresponding boiling temperatures which are used in the apparatus, the steam generated from water containing quartz is considerably purer than the water from which it originated. The apparatus includes a boiler supplied with de-ionized water. The boiler has a steam generating chamber and level indicators to provide sensing of overfill and underfill levels, respectively. Steam passes out of the boiler chamber into and through a large number of small vent holes into another chamber containing quartz pieces. Droplets collect on these quartz pieces and either evaporate or gravitate and return to the boiler chamber. All parts of the apparatus of the apparatus are made of quartz except the dump valve body which is constructed from plastic material.

Abstract: A method and apparatus for growing semiconductor quality oxide thermal layers on semiconductor wafers fast enough to be economically feasible as a batch wafer process system. Process speed is insured by high pressure and high temperature. For example, if the pressure is about 10 to 25 atmospheres and at a temperature of 600.degree. C. to 1100.degree. C., approximately 90.0 minutes are required to grow a 5,000 .ANG. oxide layer on about 50 wafers in a steam environment. The system can reach these operating conditions from ambient in approximately 17 minutes and depressurization and cool down require approximately 22 minutes. The apparatus includes a processing chamber to be pressurized with an oxidant, such as high pressure steam or oxygen. The process chamber is contained in a pressure vessel adapted to be pressurized with an inert gas, such as nitrogen, to a high pressure.