Gate current degradation mechanisms of GaN high electron mobility transistors

In spite of their extraordinary performance, GaN HEMTs still lack solid reliability. Gate current degradation during RF power device operation is a great concern because it impacts PAE, gain, and output power. In this paper, we have experimentally studied gate current degradation under high forward and reverse bias conditions on the gate. We find that strong reverse bias on the gate produces defects that become paths for excess I-G. On the other hand, strong forward bias on the gate degrades Schottky junction probably due to thermal effects.