ELECTRONIC TRANSPORT-PROPERTIES OF A-SI-Y-H ALLOY-FILMS DEPOSITED BY RF-SPUTTERING

Conductive n-type a-Si-Y-H alloy films with conductivity as high as 60 S/cm have been deposited on Si substrates by rf sputtering. The condu ctivities of the obtained films with various Y contents varying from 3 .9 to 20.6% have been measured in the temperature range from 20 to 500 K. Above room temperature (300-500 K), the plot of log a vs. 1/T can be fitted by two linear functions with different slopes and the corres ponding temperature of the kink between the two straight lines depends on the Y content in the samples. In the temperature range of 20-300 K , for samples with large Y contents (larger than 8.4%), thermally acti vated conduction is also observed. For small Y content films (smaller than 7.7%), the conductivities can be fitted to the function log sigma = A - B/T-1/4. The present results are interpreted using different el ectronic transport mechanisms in different temperature ranges and for samples with different Y contents.