The Ka-band based study on the optimised bias current density performance of cubic wide band gap semiconductor impatts and its comparison with silicon counterpart

A simulation study at Ka-band window frequency at 35 GHz has been carried out to analyse and explore the DC and high frequency properties of cubic polytypic wide band gap semiconductor DDR impatts based on 3C-SiC and ZnB-GaN. The chosen structure is a flat profile p⁺pnn⁺ DDR impatt which is optimised at a particular bias current density with respect to efficiency and output power including the effect of mobile space charge. The results obtained for the above impatts are compared with those of silicon counterpart. The simulated results obtained are very encouraging and suggest the strong potentiality of impatts based on cubic wide band gap semiconductors. The DC-to-millimetre wave conversion efficiency for cubic 3C-SiC impatt is 18.3% with an estimated output power of 34.17 W at an optimised bias current density of 2×10⁸ A/m². The conversion efficiency and estimated output power in case of cubic ZnB-GaN impatt is 50% and 2.83 W respectively at an optimum bias current density of 3.2×10⁹ A/m². Both the results are superior in comparison to the silicon counterpart for which the conversion efficiency and estimated output power at an optimum bias current density of 2.5×10⁸ A/m² are 10.1% and 2.53 W respectively. The design results presented in this paper will be very helpful to realise experimentally impatts based on cubic wide band gap semiconductors and explore their potential as a powerful millimetre wave source.