Fast surge suppression by inserting an AlGaN/GaN-based varactor

In this report, a metal-semiconductor-metal varactor diodes on top of an AlGaN/GaN-based epitaxial structure is proposed to the fast surge protection application. The fabricated device's capacitance-voltage (C-V) property and surge immunity are presented. In addition, to verify its capability for slow and fast surge absorption, three protection configurations; the gas discharge arrestor (GDA) only, in a state-of-the-art surge protection circuit, and the proposed circuit with AlGaN/GaN-based varactor were all under the system-level lightning and Electrostatic Discharge surge tests. The measured results show that the proposed fast surge protection circuit can suppress a fast intrusive pulse (FIP) voltage of 4000 V to 360 V, a reduction of 91%; whereas that suppresses to 1780 V only, a reduction of 55%, by using a traditional GDA only.