Fabrication and investigation of GaAs avalanche transit-time diodes for 60 GHz

The design, fabrication, and testing of flat-doping-profile P(+)NN(+) GaAs IMPATT diodes operating in the 50-75-GHz range are reported and illustrated with graphs and diagrams. The operating principles of IMPATT diodes are reviewed; the drift velocity of electrons under high electric fields in GaAs is investigated experimentally; and the results are applied in designing and fabricating diodes with integrated Cu heat sinks and for attachment to diamond heat sinks. The fabrication involves photolithographic etching of MBE GaAs layers to thicknesses of 1-2 microns, and the diamond-heat-sink technology permits input powers of up to 10 W for diode surface areas of about 0.00002 sq cm. The maximal output and efficiency in the lower V band are found to be 700 mW and 12.3 percent, obtained at 53 and 51 GHz, respectively; the values at 63 GHz and 72 GHz are 450 mW and 12.5 percent and 350 mW and 10 percent, respectively.