Improved surge protection of flip-chip gallium nitride-based HEMTs by metal-semiconductor-metal two-dimensional electron gas varactor

Abstract

In this paper, the authors report on the development of aluminum gallium nitride/gallium nitride (AlGaN/GaN) high electron mobility transistors (HEMTs) with improved surge protection characteristics provided by a metal-semiconductor-metal two-dimensional electron gas (MSM-2DEG) varactor connected in series to the gate of each HEMT. Under an electrostatic discharge surge stress of 1100 V or less, HEMTs that incorporate this protection feature do not exhibit any changes because the surge stress is directly blocked by the MSM-2DEG varactor. In addition, flip-chip (FC) technology is also used to further improve the thermal performance and reliability of the HEMTs. The heat generated in the 2DEG channel of the HEMT flows directly through the interconnect metal to the submount, and hence, it improves thermal conduction. The results of experiments conducted show that the proposed FC HEMT with MSM-2DEG varactor has significantly improved surge protection characteristics.

Capacitance Characteristics and Breakdown Mechanism of AlGaN/GaN Metal–Semiconductor–Metal Varactors and their Anti-Surge Application

“…This component has been widely studied and reported [9][10][11][12][13][14][15]. We have proposed GaN-based 2DEG MSM varactors as the anti-surge components connected in series between the antenna and the backend circuits, as shown in Figure 1 [16], and we have demonstrated that this design protects the back-end HEMT element from electrostatic discharge (ESD) [17]. In this study, we further apply this protection concept to MEMP attacks.…”