AVS 45th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Wednesday Sessions
       Session MI+EM-WeM

Paper MI+EM-WeM11
Magnetoresistance Properties in Granular Silicide Thin Films Formed by High Dose Iron Implantation

Wednesday, November 4, 1998, 11:40 am, Room 324/325

Session: Spin-dependent Devices: Technology and Processing
Presenter: M.F. Chiah, The Chinese University of Hong Kong
Authors: M.F. Chiah, The Chinese University of Hong Kong
W.Y. Cheung, The Chinese University of Hong Kong
S.P. Wong, The Chinese University of Hong Kong
I.H. Wilson, The Chinese University of Hong Kong
Correspondent: Click to Email
High dose iron implantation into silicon wafer has been performed with a metal vapor vacuum arc ion source (MEVVA) to doses ranging from 1*10@super 16@ to 2*10@super 17@ cm@super -2@ at various beam current densities. The magnetoresistance (MR) effects in these implanted granular layers were studied at temperatures from 15K to 300K. A positive MR effect, i.e, an increase in the resistance at the presence of a magnetic field, was observed at temperatures lower than about 70K in samples prepared under appropriate implantation conditions. The magnitude of the MR effect, defined as @DELTA@R/R@sub o@ = (R(H)-R@sub o@)/R@sub o@ where R(H) and R@sub o@ denote respectively the resistance value at a magnetic field intensity H and that at zero field, was found to depend on the implantation dose, the beam current density. This is attributed to the beam heating effect during implantation which affects the formation of the microstructures. The ratio @DELTA@R/R@sub o@ was found to attain high values larger than 500% for some samples at low temperatures. The dependence of the MR effects on temperature, implantation dose, substrate dopant concentration and beam current density will be presented and discussed in conjunction with results of Transmission Electron Microscopy and Mössbauer Spectroscopy. The phase of iron silicide, composition and depth of damaged layer were determined by spreading resistance, Rutherford backscattering and XRD measurements. This work is supported in part by a grant from the Research Grants Council of Hong Kong (Ref. No.: CUHK 374/96E)