AVS 53rd International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP7
Initial Oxidation Process of Si(100) Surface with O@sub 3@ Molecular Beam

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Surface Science Poster Session
Presenter: I. Kinefuchi, The University of Tokyo, Japan
Authors: I. Kinefuchi, The University of Tokyo, Japan
H. Yamaguchi, Nagoya University, Japan
Y. Sakiyama, The University of Tokyo, Japan
S. Takagi, The University of Tokyo, Japan
Y. Matsumoto, The University of Tokyo, Japan
Correspondent: Click to Email
The reaction of O@sub 3@ with Si(100) surface has been investigated by employing molecular beam techniques. The surfaces were oxidized at 673 K by exposure to 5.1%-O@sub 3@/O@sub 2@ beam and we examined the decomposition of the oxide adlayers using temperature programmed desorption (TPD). Compared with O@sub 2@, O@sub 3@ significantly enhances the oxidation rate in the low coverage regime. The coverage-exposure relationship up to 2.8 monolayers in thickness follows the modified Langmuirian kinetics, where the initial sticking probability of O@sub 3@ is almost unity. The desorption spectra exhibit higher peak temperatures and narrower distributions than those from the adlayers by pure O@sub 2@ beam. The surface adlayers formed with O@sub 3@ therefore have more stable and less heterogeneous structures than those formed with O@sub 2@. We also employed the molecular beam reactive scattering (MBRS) technique to investigate the reaction dynamics of the active oxidation process. The square-wave modulated beam of high concentrated O@sub 3@ gas (~60%-O@sub 3@/O@sub 2@ diluted with He) was directed to the surface at temperatures between 1033 and 1153 K. The surface transfer function shows that the reaction process is a sequential two-step first-order reaction as observed with O@sub 2@ beam. However, the reaction rate of the first step, which corresponds to the formation of the desorption precursor, is at least two times faster than that with O@sub 2@. This suggests that there is another reaction pathway involving atomic oxygen due to the decomposition of O@sub 3@ on the surface. @FootnoteText@ @footnote 1@ One of the authors (I.K.) was supported through the 21st Century COE Program, "Mechanical Systems Innovation," by the Ministry of Education, Culture, Sports, Science and Technology.