A Novel AlGaN/GaN Lateral Bipolar Junction Transistor Exploiting Polarization Effects

Gallium nitride (GaN)-based bipolar transistor has been considered highly attractive for high-power applications owing to its high breakdown voltage (BV) and high electron saturation velocity. However, achieving high current gain and high speed operations with GaN-based bipolar transistors is still a frontier challenge. In this article, a novel lateral GaN-based bipolar junction transistor (BJT) exploiting polarization effects is proposed, which is based on the epitaxy of a typical p-GaN/AlGaN/GaN high electron mobility transistor (HEMT). The conventional emitter and collector regions with n-type dopants are replaced by 2-D electron gas generated by polarization effects at AlGaN/GaN interface, and the base region is formed by Mg ion implantation. The influence of base region width on the device operating principles is investigated by TCAD simulations. Besides, the effects of n-type doping concentration in AlGaN and activated Mg-related acceptor concentration on the static characteristics of the device are investigated. It is noted that higher current gain can be achieved by utilizing higher n-doping concentration in AlGaN and smaller Mg-related acceptor concentration in the base region. The proposed BJT exhibits high BV of 480~490 V, and a maximum current gain up to 106, indicating a great prospect for high power applications featuring low power consumptions. This work provides a novel promising strategy for GaN-based Bipolar-CMOS-DMOS process based on HEMT platforms.