物質表面における光化学反応の原子レベルでの観察と制御

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We have observed the surface of Si substrate at the initial stage of the photochemical reaction inVUV-CVD process and the thin film growth in PLD method with a resolution of as atomic level. Weused the STM and the TOF for the observation. Si(111) sample which has a cleaned surface was usedas a substrate. TEOS and TEOG were used as raw materials for forming the oxide films, and Ar2*lamp (126 nm) as a light source for photo-decomposition of these materials. When the cleaned surfacewas exposed with TEOS vapor, TEOS was slightly decomposed and absorbed onto the surface. Theabsorption was found to be extremely weak. Subsequently, irradiating the VUV-radiation,photo-decomposed molecules which consist of mainly C and H were generated from the adsorption,and desorbed from the surface. After this process, molecules consisting of mainly Si and 0 wereremained on the surface. By the further irradiation, the remaining molecules were reacted with thesubstrate, and surface structure was changed. In the case of PLD, Ag was used as a target material,and Nd:YAG2 ω(532nm) used as a light source of ablation. Ag stuck on the surface in the form thatattracted several atoms. Furthermore, structural defects were found by the collision of Ag atoms onto the surface. The stuck Ag atoms were observed in the defect on the surface.
宮崎大学の論文