Dependence of catalytic properties of indium implanted SiO2 thin films on the film-substrate temperature during indium ion implantation

Chemical substances that contain indium (In) and silicon (Si) in close proximity are known to catalyze certain organic chemical reactions. An earlier paper [Yoshimura, Hine, Kiuchi, Nishimoto, Yasuda, Baba, Hamaguchi, Appl. Surf. Sci. 257 (2010) 192] has demonstrated that In implanted silicon dioxide (SiO2) films formed at room temperature catalyze a reaction of benzhydrol with acetylacetone. This study, thus, examined effects of substrate temperature during In ion implantation, revealing that, if In ions were implanted into a SiO2 film at the substrate holder temperature of 200 °C or higher, the film exhibited no catalytic ability. Surface analyses by the X-ray diffraction, the X-ray photoelectron spectroscopy, and the atomic force microscopy indicated that, at such high temperature, implanted In atoms either formed separate phases of metallic In on the SiO2 film surface or were simply nonexistent due to vaporization.