Cofabrication of Planar Gunn Diode and HEMT on InP Substrate

We present the cofabrication of planar Gunn diodes and high-electron mobility transistors (HEMTs) on an indium phosphide substrate for the first time. Electron beam lithography has been used extensively for the complete fabrication procedure and a 70-nm T-gate technology was incorporated for the enhancement of the small-signal characteristics of the HEMT. Diodes with anode-to-cathode separation (L_ac) down to 1and 120-μm width were shown to oscillate up to 204 GHz. The transistor presents a cutoff frequency ( f_T ) of 220 GHz, with power gain up to 330 GHz ( f_max). The integration of the two devices creates the potential for the realization of high-power, high-frequency MMIC Gunn oscillators, circuits, and systems.