AVS 47th International Symposium
    Surface Science Wednesday Sessions
       Session SS-WeP

Paper SS-WeP29
Photon-stimulated Ion Desorption from Mono- and Multi-layered Silicon Alkoxide on Silicon by Core-level Excitation

Wednesday, October 4, 2000, 11:00 am, Room Exhibit Hall C & D

Session: Poster Session
Presenter: G. Wu, Japan Atomic Energy Research Institute
Authors: Y. Baba, Japan Atomic Energy Research Institute
G. Wu, Japan Atomic Energy Research Institute
T. Sekiguchi, Japan Atomic Energy Research Institute
I. Shimoyama, Japan Atomic Energy Research Institute
Correspondent: Click to Email
Photo-induced processes at semiconductor surface are of great importance for the fabrication of semiconductor devices, because surface modification at low-temperature is possible using photons as a driving force of the reaction. For the deposition of silicon dioxide on silicon, silicon alkoxide is widely used for the source material. Synchrotron radiation (SR) has advantages as light source of photo-induced deposition, because of the potentiality of the element-selective and site-selective reactions due to the localized nature of inner-shell electrons. Here we present the results for the fragment-ion desorption from tetramethoxylsilane (TMS) on silicon using monochromatized SR beam around the Si K-edge. In order to separate the photochemical processes induced by substrate excitation and adsorbate excitation, we have prepared well-defined monolayer, bilayer and multilayer of TMS on Si (100). In the X-ray absorption near-edge structure (XANES) spectrum taken by total electron yield, the peak energy of the resonant excitation from Si 1s to unoccupied @sigma@* orbits for TMS was shifted to higher energy by 6 eV than that for silicon substrate. For monolayer, the desorbed fragment was only CH@sub 3@@super +@ ions. Although the XANES spectrum of monolayer was almost the same as that for silicon substrate, the photon-energy dependences of the CH@sub 3@@super +@ yield followed the XANES spectrum for TMS. The results show that the secondary electrons produced by Auger decay in silicon substrate scarcely contribute to the CH@sub 3@@super +@ desorption. And it was elucidated that the core-to-valence resonant excitation in adsorbed molecule is the main cause of the molecular-ion desorption.