title: Atomic Layer Deposition of Gallium Oxide Films as Gate Dielectrics in AlGaN/GaN Metal-Oxide-Semiconductor High-Electron-Mobility Transistors.
abstract: In this study, films of gallium oxide (Ga2O3) were prepared through remote plasma atomic layer deposition (RP-ALD) using triethylgallium and oxygen plasma. The chemical composition and optical properties of the Ga2O3 thin films were investigated; the saturation growth displayed a linear dependence with respect to the number of ALD cycles. These uniform ALD films exhibited excellent uniformity and smooth Ga2O3-GaN interfaces. An ALD Ga2O3 film was then used as the gate dielectric and surface passivation layer in a metal-oxide-semiconductor high-electron-mobility transistor (MOS-HEMT), which exhibited device performance superior to that of a corresponding conventional Schottky gate HEMT. Under similar bias conditions, the gate leakage currents of the MOS-HEMT were two orders of magnitude lower than those of the conventional HEMT, with the power-added efficiency enhanced by up to 9 %. The subthreshold swing and effective interfacial state density of the MOS-HEMT were 78 mV decade(-1) and 3.62 × 10(11) eV(-1) cm(-2), respectively. The direct-current and radio-frequency performances of the MOS-HEMT device were greater than those of the conventional HEMT. In addition, the flicker noise of the MOS-HEMT was lower than that of the conventional HEMT.
authors.affiliation: Department of Material Science and Engineering, National Taiwan University, Taipei, 10617, Taiwan.
authors.forename: Huan-Yu
authors.initials: HY
authors.lastname: Shih
authors.affiliation: Department of Electronic Engineering, Chang Gung University, Taoyuan, 333, Taiwan.
authors.forename: Fu-Chuan
authors.initials: FC
authors.lastname: Chu
authors.affiliation: Department of Electronic Engineering, Chang Gung University, Taoyuan, 333, Taiwan.
authors.forename: Atanu
authors.initials: A
authors.lastname: Das
authors.affiliation: Department of Electronic Engineering, Chang Gung University, Taoyuan, 333, Taiwan.
authors.forename: Chia-Yu
authors.initials: CY
authors.lastname: Lee
authors.affiliation: Department of Material Science and Engineering, National Taiwan University, Taipei, 10617, Taiwan.
authors.forename: Ming-Jang
authors.initials: MJ
authors.lastname: Chen
authors.affiliation: Department of Electronic Engineering, Chang Gung University, Taoyuan, 333, Taiwan. rmlin@mail.cgu.edu.tw.
authors.forename: Ray-Ming
authors.initials: RM
authors.lastname: Lin
keywords: Ga2O3; GaN; MOCVD; Metal–oxide–semiconductor high-electron-mobility transistor (MOS-HEMT); Remote plasma atomic layer deposition (RP-ALD)