GaN/Al x Ga 1− x N/GaN heterostructure IMPATT diode for D-band applications

In this paper, a novel structural impact ionization avalanche transit time (IMPATT) diode configured by GaN/Al x Ga 1− x N/GaN heterostructure is investigated at the operation frequency of D-Band. Simulation results show that, with Al composition x varies from 0.2 to 0.6, a more localized avalanche region width is obtained, the device breakdown voltage increases gradually, while the RF output power and the DC-to-RF conversion efficiency have also shown significant improvement as compared with the GaN homostructure IMPATT diode. The highest values of the RF output power density and the DC-to-RF conversion efficiency of GaN/Al 0.4 Ga 0.6 N/GaN heterostructure are obtained as 1.56 MW/cm 2 and 21.99%, larger than that of 1.02 MW/cm 2 and 16.37% for GaN homostructure IMPATT diode. Meanwhile, the lowest Q factor can be achieved, which implies that heterostructure IMPATT diodes exhibit better stability and higher growth rate of microwave oscillation compared with conventional IMPATT diodes.