Thermoelectric properties of p-type higher manganese silicide films prepared by solid phase reaction and reactive deposition

Higher manganese sificide (MnSi1.7) films are prepared on silicon and thermally oxidized silicon substrates by reactive deposition and solid phase reaction. By co-evaporation of manganese and silicon atoms on silicon substrate at about 400 degrees C, a sharp film-substrate interface is obtained. For preparation of the films on thermally oxidized silicon substrates by solid phase reaction, the oxygen level in the films is found to be dependent on the deposition rate of silicon. The oxygen and manganese atoms accumulate at the silicide-Si interface and film-SiO2 interface, respectively. The sign of the Seebeck coefficient is positive in the temperature range 300 K to 773 K, indicating the p-type conductivity of the films. The Seebeck coefficient increases with increasing temperature from 294 K to 483 K and is weakly temperature dependent above 483 K. The resistivity increases with temperature near room temperature, reaches a maximum value at about 383 K, and then decreases with further increase of the temperature. The Seebeck coefficient and resistivity at room temperature are about 114 mu V/K and 7.37 x 10(-3) Omega cm, respectively. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim