Initial oxidation of Si(100)-(2x1) as an autocatalytic reaction

Time evolutions of O 2p intensity from real-time ultraviolet photoelectron spectroscopy were obtained for the initial oxidation of Si(100)-(2 X 1) sur faces at oxygen pressures P = 7.5 x 10(-8)- 2.8 X 10(-6) Torr and temperatu res T = RT - 720 degrees C. Despite the separation of the growth mode into the Langmuir-Hinshelwood mode in the low-T-high-P region and the 2D-island growth in the high-T-low-P region, they were unifiedly described by a singl e rate equation for the oxide coverage theta, which assumes two types of su rface oxygen monomers and the number density of oxide islands that scales w ith theta(1 - theta)(2).