EFFECT OF CRYSTAL-STRUCTURE ON THE ELECTRICAL-RESISTIVITY OF COPPER-GERMANIUM THIN-FILM ALLOYS

Resistivity measurements have been performed on Cu-Ge thin-film alloys with Ge concentration ranging from 0 to 40 at. % in the temperature r ange 4.2-300 K. It is found that the dependence of resistivity on Ge c oncentration is not monotonic. This behavior is correlated to changes observed in the crystal structure of the alloys as the Ge concentratio n is increased. The resistivity is found to remain remarkably low (typ ically less than 10 muOMEGA cm at room temperature) over a range of Ge concentration that extends from 25 to 35 at. %, even though above 25 at. % Ge, the alloys consist of the low resistivity epsilon1-phase of Cu3Ge and of a Ge-rich solid solution.