Investigation of thermoelectric silicide thin films by means of analyticaltransmission electron microscopy

The microstructure of rhenium silicide thin films and its progress by annea ling were investigated by means of analytical transmission electron microsc opy. Sputtered amorphous films were characterised by analysis of the radial distribution function (RDF). The position of the first maximum of RDF repr esents the most probable distance between neighbouring atoms and decreases from 2.75 to 2.62 Angstrom in films with an increasing Si-content from 60 t o 75 at%. This decrease correlates with the change of the temperature coeff icient (TC) of the electrical resistivity. During in situ annealing, the fo rmation of nanocrystals in films with different Si-contents was observed. I n thin films with 64 at% the quantity of nanocrystals increases after 1 h a t 900 K whereas their sizes remain unchanged. The crystallisation in Re-ric h thin films proceeds lower and produces larger crystals than in films near to the ReSi1.75 stoichiometry. Sputtered epitaxial ReSi1.75 films on Si (1 0 0) consist of crystals with nanometer size and an azimuthal torsion of 4 5 degrees. (C) 2000 Elsevier Science B.V. All rights reserved.