Intermodulation generation by electron tunneling through aluminum-oxide films

The generation of intermodulation (IM) interference by nonlinear conduction mechanisms in normally passive hardware components can lead to severe degradation in the performance of multi-carrier communication systems in satellites, space probes, and ship-board systems. This paper describes an investigation of the generation of IM due to nonlinear conduction by electron tunneling through aluminum-oxide films. Details are presented regarding the fabrication of Al-Al2O3-Al junctions, the current-voltage and capacitance characteristics, and the measurement of IM power levels. The IM is correlated with the junction circuit parameters and with tunneling theory. Results are also presented on preliminary experiments to beneficially modify such nonlinear conduction by implantation of metallic ions in the oxide film.