title: DC Characteristics of AlGaN/GaN HEMTs Using a Dual-Gate Structure.
abstract: Multiple techniques such as fluoride-based plasma treatment, a p-GaN or p-AlGaN gate contact, and a recessed gate structure have been employed to modulate the threshold voltage of AlGaN/GaN-based high-electron-mobility transistors (HEMTs). In this study, we present dual-gate AlGaN/GaN HEMTs grown on a Si substrate, which effectively shift the threshold voltage in the positive direction. Experimental data show that the threshold voltage is shifted from -4.2 V in a conventional single-gate HEMT to -2.8 V in dual-gate HEMTs. It is evident that a second gate helps improve the threshold voltage by reducing the two-dimensional electron gas density in the channel. Furthermore, the maximum drain current, maximum transconductance, and breakdown voltage values of a single-gate device are not significantly different from those of a dual-gate device. For the fabricated single- and dual-gate devices, the values of the maximum drain current are 430 mA/mm and 428 mA/mm, respectively, whereas the values of the maximum transconductance are 83 mS/mm and 75 mS/mm, respectively.
authors.forename: Sejun
authors.initials: S
authors.lastname: Hong
authors.forename: Abu ul Hassan Sarwar
authors.initials: Au
authors.lastname: Rana
authors.forename: Jun-Woo
authors.initials: JW
authors.lastname: Heo
authors.forename: Hyun-Seok
authors.initials: HS
authors.lastname: Kim