THE COMPOSITION DEPENDENCE OF SOME ELECTRICAL-PROPERTIES OF FESIX THIN-FILMS

The composition dependence of the Seebeck coefficients and the microstructures of FeSix thin films were studied. In the region of x2.06, the Seebeck coefficients and amounts of the FeSi2 phase increase with increasing x. The results of electrical resistivity measurements and the analysis of the constituent phases indicate that there are two forms of the FeSi phase. In one form, the FeSi phase exists continuously along the grain boundary of the FeSi2 phase and in the other, it is surrounded by FeSi2. In the region of x>2.08, the Seebeck coefficient is negative. From the results of the d-spacing measurements, it is inferred that the excess Si in the sample with x>2.08 induces structural defects in the FeSi2, which provides the donor. © 1990 The Japan Society of Applied Physics.