Development of an appropriate model for the design of D-band InP Gunn devices

The potential of InP Gunn devices as power sources in the fundamental mode at D-band frequencies (110 GHz-170 GHz) is investigated. A self-consistent ensemble Monte Carlo model has been developed to design and identify suitable structures for operation in this frequency range. Using this model with typical InP material parameters found in the literature will be shown to give results inconsistent with experiment. Based on experimental results from a 1.7 μm long Gunn structure, more realistic material parameters were estimated. The resulting model is then used to design various structures with active regions in the 1 μm range. In particular, two structures, one with a flat doping profile and the other with a linearly graded doping profile, were fabricated and tested. State-of-the-art performance from these structures operating in the fundamental mode was obtained at frequencies ranging from 108.3 GHz to 155 GHz. The flat structure yielded optimum results at 108.3 GHz with a power level of 33 mW while the graded structure gave 20 mW at 120 GHz, 17 mW at 133 GHz, 10 mW at 136 GHz, and 8 mW at 155 GHz. These results will be compared with the model predictions.