PHASE-FORMATION AND TRANSPORT-PROPERTIES IN AMORPHOUS AND NANOCRYSTALLINE CRXSI1-X AND REXSI1-X THIN-FILMS

Experimental data on the structure and electronic transport properties of RexSi1-x and CrxSi1-x thin films are presented. The composition x varies around the value corresponding to the Re- and Cr-disilicides. N anocrystalline films were obtained from an amorphous state by heat tre atment procedures. From the electrical resistivity and thermoelectric power measurements and X-ray investigations performed in the course of the heat treatment, the activation temperatures of crystallization of the semiconducting CrSi2 or ReSi2 compounds were determined to be abo ut 630 and 850 K. Above this crystallization temperature the film cons ists of the nanodispersed grains of the crystalline disilicide in amor phous Si or Si-M matrix (where M is Cr or Re). In a broad range of ann ealing temperatures, the crystallization progresses due to increasing number of nanocrystalline grains with an average size of 20-50 nm. Ana lysis of the transport properties of the films measured in the tempera ture range from 300 up to 1300 K reveals that they do not conform to t he prediction of the commonly used effective medium approximation.