THEORETICAL-ANALYSIS AND FABRICATION OF SMALL-AREA METAL INSULATOR RESONANT-TUNNELING DIODE INTEGRATED WITH PATCH ANTENNA FOR TERAHERTZ PHOTON-ASSISTED TUNNELING/

Alternative voltage induced across a resonant tunneling diode under th e THz radiation, which is an important factor for photon assisted tunn eling, is theoretically analyzed in general form. As an application, i ntegration of a small-area resonant tunneling diode with a circular pa tch antenna is proposed. A patch antenna has high radiation directivit y and suitability for a diode with vertical layer structure on a high- doped substrate. Size of he antenna and diode necessary to reduce the loss and capacitance was discussed taking into account fabrication lim it. The estimated voltage in this integrated device together with an a ppropriate lens system is comparable to the THz photon energy under re latively low power radiation (similar to 100 mW). To achieve requireme nt of the device size, a fabrication process is investigated for a 1 m m-diameter metal/insulator (CoSi2/CaF2) resonant tunneling diode with a patch antenna. Fabricated diodes show negative differential resistan ce in static characteristics with the maximum peak-to-valley ratio of 2.8 at room temperature. (C) 1998 Elsevier Science Std. All rights res erved.