Mechanistic studies of silicon oxidation

The microscopic mechanism of the formation of ultrathin oxides on Si(100) h as been investigated using a combination of infrared spectroscopy and ab in itio quantum chemical cluster calculations. The 0-->2 monolayer oxide films are grown sequentially from the "bottom-up" using repeated water exposures and annealing cycles, with the partial pressure of water ranging from 10(- 10) to 10 Torr. The resultant films were then compared to the equivalent th icknesses of thermal and native oxide films. In this way, we obtain unprece dented insight into the essential chemical structures formed during the ini tial oxidation and subsequent layer growth of these technologically relevan t films. (C) 1999 American Vacuum Society. [S0734-211X(99)02804-8].