High electron mobility effect in band-engineered GaN/quasi-AlGaN based exotic avalanche transit time diode arrays: application as ultra fast THz switches

Abstract

Band-engineered GaN/quasi-AlGaN material system is suitably deployed for designing high power RF switches in THz domain. Unique superlattice-based, quasi-AlGaN barrier results in increase of electron effective mass along the growth direction. That in turn results in excellent quantum confinement at the quasi-AlGaN/GaN interface. This is coupled with the ingenious lateral orientation of the proposed Avalanche-Transit-Time (ATT) diode and the use of prototypal Cathode Field Plate (CFP). The cumulative effect of such prototypical features leads to the formation of very high mobility 2DEG active region. To the best of authors’ knowledge this is the first ever study on high electron mobility effect in two-terminal ATT devices. An indigenously developed strain-corrected quantum modified large signal drift–diffusion model is developed for analyzing the performance of the proposed device. Study reveals that RF power output ~$1\times {10}^{12}\mathrm{W}/{\mathrm{m}}^{2}$ at 1 THz, can be obtained from a single device incorporating series resistance effect. In case of array type devices the power output enhances by almost 20%. Further, the SPST, SPDT and SPMT switch models have been designed and compared.