CONDUCTIVITY OF RF-SPUTTERED NI-100-X-SI-X THIN-FILMS WITH 3-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-77 AT.PERCENT

The temperature dependence of the electrical resistance of r.f.-sputte red Ni-Si thin films with variable Si content in the range 33-77 at.% (as determined by Rutherford backscattering spectroscopy) was measured between - 190 degrees C and the annealing temperature T-t (T-tmax=300 degrees C). The as-deposited films were investigated by X-ray diffrac tion and transmission electron microscopy, and were found to exhibit a n amorphous structure (different from that of amorphous Si), except th ose films with a composition favourable for silicide formation. The te mperature dependence of the conductivity of these films is interpreted in the framework of the weak localization model and electron-electron interactions. Annealing at 300 degrees C brings about a transformatio n from an amorphous structure into a microcrystalline structure compri sing different silicides, whose electrical resistance displays a class ical metallic temperature dependence, except for the sample with x = 7 7 at.%, which remains amorphous, although its conductivity increases w ith temperature.