Physics-Technological Fabrication Features and Parameters of InP MM-Wave Gunn Diodes

We developed (i) a technology to form Au-Ge-TiB_x-Au ohmic contacts to indium phosphide Gunn diodes on the basis of n-n⁺ -n⁺⁺ epitaxial structures made on the standard and porous n⁺⁺-InP substrates, (ii) batch-fabrication technique for mesas with gold heat sink, and (iii) technique for diode chip packaging in a metal-quartz package. It is shown that the Gunn diodes of both types (on the standard and porous substrates) ensure generation of microwave power in the 88-98 GHz frequency range. When operating under normal climatic conditions and at a temperature no less than -40degC, the power output P_out of the Gunn diodes made on the porous substrates is over that of the ones made on the standard substrates. At package temperature of +75degC, the power output of the Gunn diodes of both types decreases, with P_out value of the diodes made on the porous substrate becoming somewhat below that of the ones made on the standard substrate. We suppose that the reason for P_out decrease is the temperature dependence of thermal conductivity which is different in the standard and porous InP