Experimental Investigation of GaN-on-AlN/SiC Transistors With Regard to Monolithic Integration

The monolithic integration of the GaN-on-Si high-electron-mobility transistors (HEMTs) is challenging since the back-gating effects caused by a common substrate degrade the device's performance. In this article, we introduce novel GaN-on-AlN/SiC power HEMTs. Compared with conventional GaN-on-Si HEMTs, the presented transistors show immunity to back-gating effects, thereby enabling monolithic integration of power devices without degradation of performance. Discrete power HEMTs are characterized systematically regarding both static and switching characteristics with a focus on the impact of the substrate potential. Furthermore, monolithic GaN-on-AlN/SiC half-bridges and monolithic GaN-on-AlN/SiC bidirectional switches are fabricated using the same device technology. The switching characteristics of these monolithically integrated devices are also investigated for different substrate terminations. It is demonstrated that both discrete and monolithically integrated devices achieve stable and fast switching and show a satisfactory back-gating immunity.