EXPERIMENTAL STUDY OF LOW-FREQUENCY EXCESS (1/F) NOISE IN METAL FILMS
Abstract
We have performed an extensive study of the 1/f noise of several different kinds of metal films. We find that the noise of Sn and In films at room temperature is influenced by the choice of substrate; however, we find no such dependence for the other materials studied (Ag, Au, Cu, Pb, Bi, AuPd, Pt, and Au(,x)Ag(,1-x)). Evidence is presented that the noise of Pt films and ultrathin Pt wires arises from a bulk fluctuation. Further, the large sample-to-sample variations of the noise (even among nominally identical samples), the striking time-dependent behavior of the noise of some samples, and the effect of strain on the noise are carefully documented. These results suggest that much, if not all, of the 1/f noise found in metal films is due to defect motion. Striking confirmation of this idea was found in a study of the dependence of the noise on temperature and annealing for a disordered alloy of AuPd. Not only do we find that the model of Dutta and Horn provides an excellent description of the noise for this system, but these results are also in excellent agreement with one's expectations concerning the effects of annealing on a disordered system. This suggests that noise measurements could be used as a probe of defect concentrations, perhaps in a range of defect energies that would otherwise be inaccessible in these systems.
Degree
Ph.D.
Subject Area
Condensation
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