Au-free AlGaN/GaN heterostructure field-effect transistor with recessed overhang ohmic contacts using a Ti/Al bilayer. (29th June 2015)

• Record Type: Journal Article
• Authors: Lee, Jae-Gil; Kim, Hyun-Seop; Kim, Dong-Hwan; Han, Sang-Woo; Seo, Kwang-Seok; Cha, Ho-Young
• Is Part Of: Semiconductor science and technology. Volume 30:Number 8(2015:Aug.)
• Publication Date: 2015-06-29
• Subjects: AlGaN/GaN -- ohmic -- Au-free -- HFET; Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/0268-1242/30/8/085005
• Languages: English
• ISSNs: 0268-1242

Abstract

Abstract: We have developed a low-temperature ohmic contact process with a recessed overhang configuration for Au-free (complementary metal-oxide semiconductor) CMOS-compatible AlGaN/GaN heterostructure field effect transistors (HFETs). The recessed overhang configuration has a Ti/Al bilayer directly in contact with the AlGaN/GaN heterojunction interface at the recessed sidewall overlaid with the AlGaN barrier layer, which allows good and reproducible ohmic formation with low-temperature annealing. The optimum Ti/Al thickness was 40/200 nm, which resulted in an R c of 0.76 Ω mm with excellent surface morphology when annealed at 550 °C for 1 min. The device fabricated with a Ni/Mo gate exhibited a maximum drain current density of ∼500 mA mm −1, a specific on-resistance of 1.35 m Ω cm 2 and a breakdown voltage of >1 kV.