The diffusion of C in oxide films, and its segregation at Si/SiO2 interfaces, were investigated by using C-containing borophosphosilicate glass films and C-implanted SiO2 films. It was found that C atoms diffused in oxide films at temperatures as low as 500C. The C atoms segregated at the Si/SiO2 interface and induced a positive charge. The positive charge density was proportional to the segregated C concentration. Field emission transmission electron microscopy and electron energy loss observations revealed that C atoms existed on the SiO2 side of the interface, and that another C-rich phase formed in SiO2.

I.Mizushima, E.Kamiya, N.Arai, M.Sonoda, M.Yoshiki, S.Takagi, M.Wakamiya, S.Kambayashi, Y.Mikata, S.Mori, M.Kashiwagi: Japanese Journal of Applied Physics - 1, 1997, 36[3B], 1465-8