High-Performance Normally-OFF AlGaN/GaN Fin-MISHEMT on Silicon With Low Work Function Metal-Source Contact Ledge.

We demonstrate a high-performance normally-OFF AlGaN/GaN fin metal–insulator–semiconductor high electron mobility transistor (fin-MISHEMT) on silicon with a low work function metal-source contact ledge (LWFM-SCL). In order to realize the normally-OFF operation, an optimized gate-recessed fin structure is used. The fin structure inherently containing a gate-connected field plate (FP) design improves the breakdown voltage (VBD). Moreover, the LWFM-SCL can improve the device overall ON-resistance (RON) by lowering the gate–source access resistance (Ra). The proposed device with a gate–drain length (LGD) of 7 μm exhibits superior characteristics such as a threshold voltage (VTH) of +1.2 V, maximum drain current (ID, max) of 825 mA/mm, ON-state/OFF-state current (ION/IOFF) ratio of 109–1010, subthreshold swing (SS) of 76 mV/decade, VBD of 810 V, and specific RON (Ron, sp) of 0.63 mΩ ⋅ cm2. It also possesses excellent VTH hysteresis, temperature stability, and dynamic RON characteristics. These results suggest that the proposed device is very suitable for high power switching applications. [ABSTRACT FROM AUTHOR]