title: Formation of gallium vacancies and their effects on the nanostructure of Pd/Ir/Au ohmic contact to p-type GaN.
abstract: The properties of Pd/Ir/Au ohmic metallization on p-type GaN have been investigated. Contacts annealed at 400 degrees C in O2 atmosphere demonstrated excellent ohmic characteristics with a specific contact resistivity of 1.5 x 10(-5) Omega-cm2. This is attributed to the formation of Ga vacancies at the contact metal-semiconductor interfacial region due to the out-diffusion of Ga atoms. The out-diffusion of Ga atoms was confirmed by X-ray photoelectron spectroscopy depth profiles, high-resolution transmission electron microscopy, and electron energy loss spectroscopy using a scanning transmission electron microscope.
authors.affiliation: Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 440-746, Korea.
authors.forename: Kyong Nam
authors.initials: KN
authors.lastname: Kim
authors.forename: Tae Hyung
authors.initials: TH
authors.lastname: Kim
authors.forename: Jin Seok
authors.initials: JS
authors.lastname: Seo
authors.forename: Ki Seok
authors.initials: KS
authors.lastname: Kim
authors.forename: Jeong Woon
authors.initials: JW
authors.lastname: Bae
authors.forename: Geun Young
authors.initials: GY
authors.lastname: Yeom