Recent advances in the performance of GaAs- and InP-based two-terminal devices as high-power millimeter-wave sources

Advanced growth techniques for nanometer-scale devices at millimeter- and submillimeter-wave frequencies are mature and readily available to produce the required epitaxial material. Selective etching techniques allow precise fabrication control. Layer structures for diodes with low-noise interband tunneling as the predominant injection mechanism were designed using a simple unified large-signal analysis and grown by molecular-beam epitaxy (MBE). These tunnel injection transit-time (TUNNETT) diodes on diamond heat sinks yielded up to 100 mW between 100 GHz and 105 GHz with corresponding dc-to-RF conversion efficiencies of up to 6%. Excellent FM noise measures of between 22 dB and 26 dB at high power levels were obtained, and noise measures below 18 dB at intermediate power levels are the lowest reported for any oscillator utilizing two-terminal devices in this frequency range. RF power levels and dc-to-RF conversion efficiencies exceed those of GaAs Gunn devices in the same frequency range