AVS 52nd International Symposium
    Thin Films Monday Sessions
       Session TF-MoP

Paper TF-MoP6
Isotopically Concentrated Silicon Film Formation by Chemical Vapor Deposition

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Aspects of Thin Films Poster Session
Presenter: H. Yamamoto, Japan Atomic Energy Research Institute
Authors: H. Yamamoto, Japan Atomic Energy Research Institute
H. Ohba, Japan Atomic Energy Research Institute
M. Sasase, The Wakasa-wan Energy Research Center, Japan
K. Yamaguchi, Japan Atomic Energy Research Institute
K. Shimura, Japan Atomic Energy Research Institute
S. Shamoto, Japan Atomic Energy Research Institute
A. Yokoyama, Japan Atomic Energy Research Institute
K. Hojou, Japan Atomic Energy Research Institute
Correspondent: Click to Email
Isotopically concentrated silicon (@super 30@Si) film has been attempted to form by means of chemical vapor deposition. The natural isotope @super 30@Si can be transmuted into stable @super 31@P by the capture of a thermal neutron. If the @super 30@Si enriched layer is formed on the @super 28@Si or natural Si substrate, the enriched layer can act as "donor doping layer" by the transmutation. However, it is hard to obtain plenty of enriched @super 30@Si, since its natural abundance is only 3.1%. Recently, a method for highly efficient enrichment of @super 30@Si in a form of @super 30@SiF@sub 4@ has been established by Yokoyama et al.@footnote 1@ In the present study, the @super 30@Si enriched film (~several tens nm) was deposited on natural Si substrate by using RF plasma (13MHz, 300W) from gaseous mixture of SiF@sub 4@ and H@sub 2@ diluted with Ar. The optimum condition of Si deposition has been investigated by using natural SiF@sub 4@. Obtained film was characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). XPS results showed that an impurity phase appeared in the deposited film depending on the H@sub 2@/SiF@sub 4@ gas flow rate ratio and temperature during deposition. For example, the film contained ~10at.% of fluorine in the case of the gas ratio of 2~4 at 250°C. Even though the fluorine content decreased drastically with the increase of the gas ratio up to 10, it still remained at this temperature. The fluorine was not observed in the sample deposited at 400°C. Results of the other analyses will be also presented and discussed. @FootnoteText@ @footnote 1@A.Yokoyama, H.Ohba, et al., Appl.Phys.B 79 (2004) 883-889.