Effects of annealing and crystallization process in amorphous SiGe alloy films

Abstract

The change of the structure and the process of crystallization after annealing are investigated by ESR, electrical measurement and X-ray microanalysis for amorphous Si 57Ge 43 thin films prepared by rf-sputtering. It is found that the lorentzian ESR lineshape and linewidth are independent of annealing temperature, while the g-value approaches that for a-Ge with annealing, and the temperature dependence of conductivity obeys the Mott relation. After annealing at rather higher temperature, the non-uniformity of the spatial distribution of Si and Ge atoms is observed. As a result it is suggested that unpaired electrons responsible for ESR and conductivity] exist mainly in Ge sites after annealing and the wave function is most likely to extend over several atomic sites in which the ratio of the number of Ge atoms to that of Si atoms increases with annealing.