Local neutron transmutation doping using isotopically enriched silicon film

Yamada, Yoichi; Yamamoto, Hiroyuki; Oba, Hironori  ; Sasase, Masato*; Esaka, Fumitaka  ; Yamaguchi, Kenji; Udono, Haruhiko*; Shamoto, Shinichi  ; Yokoyama, Atsushi; Hojo, Kiichi

Si in natural Si has been widely used for a doping source, since Si can be transmuted into P by thermal neutron (Neutron Transmutation Doping, NTD). NTD of nanostructure fabricated from Si-enriched materials can serve as a controlled local doping method with tunable dopant concentration, which cannot be realized by conventional doping methods such as ion implantation. In the present study, Si-enriched thin film has been fabricated in order to demonstrate the local NTD. The Si-enriched film with thickness of 100 nm was deposited on the Si(100) substrate by plasma enhanced chemical vapor deposition using Si-enriched SiF as the source gases. The film contains 7.1 % of Si, which is twice higher than that of natural Si. Possible contaminant, fluorine, is lower than 0.6 at.% determined from X-ray photoelectron spectra. Nanostructure of films and changes of electronic properties by the neutron irradiation will also be discussed.