Structure and morphology of Ge(Au) sputtered films with useful Seebeck effect

The results of investigations concerning the structural and the thermoelectric properties of Ge(Au) sputtered films under pulsed voltage operation of magnetron are described. The film properties are discussed as a function of doping with gold (2 and 5 at%) and the substrate temperature during deposition (360-1040 K). Almost all as-deposited films were polycrystalline and contained crystallites of both Ge and Au phases. The Seebeck coefficient and the electrical conductivity were observed to increase with increasing substrate temperature during sputtering. In general, depending upon the sputtering conditions, compressive or tensile stresses of the order of - 1.8x 10(8) Pa to 2.7x 10(8) Pa were observed in Ge. The tensile stress in Au was observed to increase with increasing substrate temperature. The experimental results are discussed in terms of microstructure changes. The proper deposition conditions for optimizing internal stress, Seebeck coefficient and film resistivity can be obtained. (C) 1998 Elsevier Science Ltd. All rights reserved.