AlGaN/GaN bilateral IMPATT device by two-dimensional electron gas for terahertz application

A novel bilateral impact-ionization-avalanche-transit-time (BIMPATT) diode based on AlGaN/GaN two-dimensional electron gas is proposed in this article. The BIMPATT is compatible with the available GaN high electron mobility transistor (HEMT) manufacturing process and has a shorter actual electron transit distance than existing HEMT-like IMPATT (HIMPATT) diodes. Compared with the same-sized HIMPATT, the optimum frequency of BIMPATT rises from 320 to 420 GHz and possesses a far wider operating frequency band, especially in the near 0.9 THz range. The maximum DC-RF conversion efficiency rises from 12.9% to 17.6%. The maximum RF power of BIMPATT is 3.18 W/mm, which is similar to 3.12 W/mm of the HIMPATT. Furthermore, our simulation demonstrated that the characteristics of BIMPATT are significantly affected by the length of anode and the thickness of the AlGaN barrier layer. The effects of ohmic contact resistance and background impurities on BIMPATT are also taken into account. This paper provides a reference for the design and characteristics enhancement of the lateral IMPATT devices.