Scaling of GaN FinFETs on 4 Inch Silicon Carbide from 20 to 150 Fins with Maximum Frequency of Oscillation fmax = 20.4 GHz

The fin field-effect transistor (FinFET) is a promising candidate among vertical GaN-based transistors as it is inherently unipolar and requires neither p-type doping nor regrowth processes. While commonly regarded as a high power device, recent research has started to explore its potential as a high frequency transistor. In our previous work, we demonstrated a small-signal current gain of f t = 10.2GHz for a FinFET with 20 fins. More recently, we presented our investigations on the scaling of the fin length and its influence on the small-signal performance based on FinFETs processed on 3 inch sapphire substrate. In this work, we expand our studies to investigate the scaling effect of the number of fins in FinFETs, and report new record values for the maximum frequency of oscillation f max for vertical GaN transistors.