PREPARATION OF NANOCRYSTALLINE SILICON CARBIDE FILMS WITH HIGH SEEBECK COEFFICIENT AND LOW RESISTIVITY

Abstract

Nanocrystalline silicon carbide ( SiC ) thin films with 5 ~ 10 nm grain size, large Seebeck coefficient (-0.393 mV/K), and low electrical resistivity (3.2 ×10-4 Ohm-m) have been successfully prepared on oxidized silicon substrates by magnetron sputtering of SiC and Al targets. It was found that the addition of a small amount of Al into the SiC film, the high deposition temperature (760 K), and the high thermal annealing temperature (1063 K) were necessary to achieve the goal. The Seebeck coefficient versus logarithm of temperature in the temperature range 383 K to 533 K was a straight line with a slope of -0.999 mV/K. The value of 0.999 mV/K is much larger than the theoretical value of 0.129 mV/K for conventional semiconductors.