GaN/AlGaN Hetero-junction Terahertz

A simulation study is carried out on the hetero-structure complementary (p-p-p-n) IMPATT oscillator for Terahertz power generation. It is observed that hetero-structure GaN/AlGaN IMPATT may generate a pulsed power density of ~8x10 Wm with an efficiency of 11%, whereas it’s flatly doped counterpart is capable of delivering a pulsed power density of only 3x10 Wm with 7% efficiency. The total parasitic series resistance, RS, including that due to the un-depleted region in device and also the effects of ohmic contact resistances, has been found to be a major problem that reduces the negative resistance significantly and thus it has a affects the THz performance and oscillation of the device. The study reveals that the value of RS decreases by ~50% as the structure, semiconductor material pair as well as doping profile of the diode changes suitably from conventional to the proposed hetero-structure p-p-p-n type , by incorporating a 300A Al0.4Ga0.6N layer in the p-drift region. This first study will be a useful guide in the THz-sector to meet the ever-increasing demand of semiconductor THz-sources for application in Imaging or in improvised explosive device (IED) detection.