Novel Asymmetric Slant Field Plate Technology for High-Speed Low-Dynamic Ron E/D-mode GaN HEMTs

Abstract

In this letter, we discuss a novel asymmetric field plate structure utilizing a slanted field plate (FP) engineered to appropriately distribute the electric field on GaN high-electron mobility transistors (HEMTs) scaled for low-loss, high-speed power switch applications. A uniform electric field distribution achieved with the slant FP enables an optimum device design, where a low-dynamic ON-resistance ( $\text{R}_{\textsf {on,dyn}}$ ) and high breakdown voltage are obtained simultaneously by minimizing the gate-drain distance. The optimized FP design demonstrated a low $\text{R}_{\textsf {on,dyn}}$ of 2.3 (2.1) $\Omega $ -mm at a quiescent drain voltage of 50V in $\mathsf {E}$ -mode ( $\mathsf {D}$ -mode) HEMTs with a breakdown voltage of 138 V (146 V). The corresponding high-frequency performance of E-mode (D-mode) HEMTs of peak $\text{f}_{\textsf {T}}/\text{f}_{\textsf {max}}= 41$ /100 GHz (53/100 GHz) yielded a decent $\text{R}_{\textsf {on,dyn}} \times \text{Q}_{\textsf {g}}$ product in the range of 31.0–34.5 (28.0–33.3) $\text{m}\Omega \vphantom {^{\int }}$ -nC. This new slant FP technology combined with scaled epitaxial structure (for short $\textsf {L}_{\textsf {g}}$ ) and reduced access resistances, using n+ GaN ohmic contacts, greatly enhances performance and design flexibility of high-speed, low-loss, GaN power switch devices.