Development and application of surface analysis apparatus using electron-ion coincidence spectroscopy

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In 2000-2001 fiscal year we have developed a new electron-ion coincidence (EICO) apparatus composed of a coaxial symmetric mirror electron energy analyzer proposed by Kai Siegbahn, a compact time-of-flight ion mass spectrometer and a positioning mechanism. Auger electron photoion coincidence (AEPICO) measurements of condensed H_2O at 4α_1 ← O 1s resonance showed that time required for a certain coincidence ioin counts is reduced by one order of magnitude in comparison with the previous EICO analyzer using a CMA. With the apparatus we studied fluorination of Si(111) surfaces by XeF_2 using Si 2p - F^+ photbelectron photoion coincidence (PEPICO) and Si 2p photoelectron sjpectroscopy (PES), and found that fluorination of the top-most Si layer proceeds after the initial XeF_2 exposures, while fluorination of the second Si layer starts in 6400-9600 L. In 2002 fiscal year, we have developed a new polar-angle-resolved compact time-of-flight ion mass spectrometer (TOF-MS). The TOF-MS consists of an electric field shield, an ion drift electrode with three meshes, and micro channel plates (MCP) with three concentric anodes. Using it we developed electron - polar-angle-resolved-ion coincidence analjyzer, which offers information on kinetic energy and desorption polar angle of coincidence ions. Its performance was evaluated by measuring H^+ yield spectra and Auger electron - H^+ coincidence spectra of a condensed H_2O. We have written three review articles on EICO spectroscopy. We also reported a PEPICO study on site-specific ion desorption of CF_3CD(OH)CH_3 chemisorbed on Si(100), and a EICO study on H^+ desorption induced by shake up and shake off ionizations of O 1s of H_2O dissociatively chemisorbed op Si(100).