A comparative study of simulated and experimentally obtained nonuniformity in thermal and electrical properties of conducting films

摘要

The effect of localized microwave absorption in conducting thin films had been simulated using a heat diffusion model to quantitatively evaluate the electrical voltage maps obtained recently using a near-field scanning microwave microprobe (NSMM) in combination with the Ⅰ-Ⅴ characterization. In the experiment, the focused microwave emitted from the NSMM at a sample spot of dimension comparable to the NSMM tip dimension changes the local resistivity of the sample via microwave heating. By measuring the voltage response while scanning the NSMM, nonuniformity in the electrical current distribution in the sample can be resolved. To quantitatively assess the effect of various parameters, a theoretical simulation of the temperature profile has been made and related to the voltage response profile obtained experimentally. The variation of the induced voltage due to microwave absorption with time, microwave input power, and the thickness of the film has also been studied and the simulation compares well with experiment. Discussions on discrepancies between simulation and experiment will also be presented.