MOVPE-grown millimeter-wave InGaAs mixer diode technology and characteristics

The merits of InGaAs-based millimeter-wave mixer diodes are explored experimentally and theoretically. Schottky junctions on InGaAs exhibit barriers (/spl phi//sub b/) in the neighborhood of 0.25 eV. The high mobility of InGaAs contributes to the low n/sup +/ sheet resistances of 1.9-5 /spl Omega//square for 1-/spl mu/m n/sup +/ InGaAs layers (n/sub s/=1.5/spl times/10/sup 19/ cm/sup -3/, /spl mu//sub n/=1800 cm/sup 2//V/spl middot/s) grown with our in-house Metalorganic Vapor Phase Epitaxy (MOVPE) system, The design, material growth, fabrication, and characterization of InGaAs integrated mixer/antennae are reported. Pt plating technology, adapted here for InGaAs Schottky contacts, has improved the ideality factor (/spl eta/) and yield relative to conventional evaporated Pt. With 810 /spl mu/W of local oscillator power, applied to the diode, and zero DC bias, an integrated InGaAs mixer/antenna demonstrated an excellent diode performance of 199 K RF input double-sideband noise temperature with a corresponding single-sideband (SSB) conversion loss (L/sub c/) of 5.0 dB at LO, RF, and IF frequencies of 94 GHz, 94 GHz/spl plusmn/1.4 GHz, and 1.4 GHz, respectively. Likewise, the diodes in an InGaAs subharmonic integrated mixer/antenna demonstrated an equivalent RF-port double-sideband (DSB) noise temperature (T/sub mix/) of 1058 K and single-sideband conversion loss of 10.2 dB at 180 GHz with a 90-GHz LO power (PLO) of 1.6 mW. Compared to GaAs diodes with RF coupling and IF losses removed, the single-ended InGaAs noise temperature results were within 46-100 K of those for state-of-the-art GaAs mixer diodes while requiring significantly less LO power.