NiO gate GaN-based enhancement-mode hetrojunction field-effect transistor with extremely low on-resistance using metal organic chemical vapor deposition regrown Ge-doped layer. (1st November 2016)

• Record Type: Journal Article
• Authors: Suzuki, Asamira; Choe, Songbeak; Yamada, Yasuhiro; Otsuka, Nobuyuki; Ueda, Daisuke
• Is Part Of: Japanese journal of applied physics. Volume 55:Number 12(2016:Dec.)
• Publication Date: 2016-11-01
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/JJAP.55.121001
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: In this paper, we present a normally-off GaN-based transistor with an extremely low on-resistance ( R on ) fabricated by using a Ge-doped n ++ -GaN layer for ohmic contacts. We developed a novel GaN regrowth technique using Ge as a dopant, which achieved an extremely high doping concentration of 1 × 10 20 cm −3, and thereby the lowest specific contact resistance of 1.5 × 10 −6 Ω·cm 2 . The NiO gate fabricated using an atomic layer deposition technique reduced the spacing between the source and drain electrodes. The fabricated device showed the record-breaking R on of 0.95 Ω·mm with the maximum drain current and transconductance of 1.1 A/mm and 490 mS/mm, respectively. Note that the obtained threshold voltage was 0.55 V. This extremely low R on characteristic indicates the great potential of NiO-gate GaN-based heterojunction field-effect transistors.