Design and Characterization of Integrated Submillimeter-Wave Quasi-Vertical Schottky Diodes

This work reports on a new approach to realizing vertically oriented Schottky diodes, with ohmic contact formed directly below the anode, that can be readily integrated into planar millimeter and submillimeter-wave circuits. The diode structure is based on backside processing and bonding of the diode epitaxy to a host, high-resistivity silicon substrate that supports both the vertical diode and its associated circuitry. A set of prototype diodes of different anode diameters are fabricated for characterization at both dc and (for the first time) submillimeter-wave frequencies (325-750 GHz) using micromachined on-wafer probes. Device equivalent circuit parameters extracted from these measurements are in good agreement with those expected from fundamental Schottky barrier diode theory and indicate the vertically oriented diodes yield series resistance values that are comparable to or lower than planar-oriented diodes of similar dimensions.