GaN 2DEG Varactor-Based Impulse Suppression Module for Protection Against Malicious Electromagnetic Interference

Abstract

A GaN-based metal–semiconductor–metal varactor with a two-dimensional electron gas (2DEG) layer is proposed and fabricated. The capacitance variation of this fabricated varactor biased at different external voltages is studied and measured, and the frequency-dependent capacitance and resistance of the varactor are simulated by a corresponding empirical formula. A high-frequency protective filter is further constructed and placed under a large pulsed-current injection in a malicious electromagnetic interference immunity test. The results show that the proposed GaN-based module can reduce the large pulsed current to an acceptably small level. Thus, the GaN-based 2DEG varactor is an attractive candidate for applications designed to protect the upcoming 5G high-frequency system from risks such as electrostatic discharge, lightning, and electromagnetic pulses.

Annealing-Dependent Breakdown Voltage and Capacitance of Gallium Oxide-Based Gallium Nitride MOSOM Varactors

“…The wafer structure is shown in Figure 1a. To obtain a more detailed manufacturing process of the MSM varactor, we can refer to our previously published literature [12]. Based on previous research results, we know that the design of the electrode structure will affect the maximum capacitance (C max ), minimum capacitance (C min ), capacitance conversion ratio (C ratio ), and breakdown voltage of the varactor.…”

“…The use of gallium nitride (GaN), which possesses good material characteristics [9,10], such as a wide energy gap, high electron mobility, and high breakdown voltage, has been previously verified by many laboratories, Materials 2020, 13, 4956 2 of 16 including ours. Measurements of an anti-surge module using an AlGaN/GaN-based two-dimensional electron gas (2DEG) MSM varactor as the key component have been carried out [11,12]. Some of these anti-surge modules can suppress the attack of malicious electromagnetic pulses to a tolerable level and meet the requirement of MIL-STD-188-125-2 [13].…”

“…To further improve the breakdown voltage of these key varactor components and to realize a more robust and reliable anti-surge module, an electron-beam evaporated Ga 2 O 3 thin film was utilized in the deposition process of this article. Thanks to the previous progress of research in MSM varactors, we are able to determine how the design of the electrode structure will affect the breakdown voltage and variable capacitance characteristics [12]. Therefore, we can attempt to further promote the breakdown voltage of an MSM varactor based on an optimized design.…”