Fabrication and Packaging of Discontinuous MIM (Metal-Insulator-Metal) Film Arrays for Efficient MM Wave and IR Detection and Mixing

摘要

Sputtering deposition of discontinuous Ni islands on a glass plate automatically produces a planar MOM diode array structure that will be mechanically stable when electrical leads are silver soldered to any two points of the coated plate. However, the efficiency in radiation reception and detection is totally controlled by the geometry of the diode array or the deposition process, which is mostly random due to deposition at very low sputtering powers. Such an array structure also has very poor antenna properties. Diode responsivity is found to be significantly improved by the incorporation of an etched-tip tungsten whisker, serving both as a long wire antenna for radiation reception and as a sharp tip electrical contact that concentrates the incident field and directs it to a selected nickel island group. This improvement in diode responsivity is offset by degradation in diode stability similar to that experienced by the MOM point contact diode, but to a lesser extent. The distinction between these two structures lies in the fact that the whisker serves mainly as an electrical contact in the discontinuous film diode, while it serves as the other electrode, sandwiching an ultrathin oxide layer, in the point contact vision. Stability can again be improved by deliberate hooking of an optimally etched tip without blunting. Some blunting is acceptable in the film diode at the expense of reduced diode responsivity.