title: Dark current reduction of Ge photodetector by GeO₂ surface passivation and gas-phase doping.
abstract: We have investigated the dark current of a germanium (Ge) photodetector (PD) with a GeO₂ surface passivation layer and a gas-phase-doped n+/p junction. The gas-phase-doped PN diodes exhibited a dark current of approximately two orders of magnitude lower than that of the diodes formed by a conventional ion implantation process, indicating that gas-phase doping is suitable for low-damage PN junction formation. The bulk leakage (Jbulk) and surface leakage (Jsurf) components of the dark current were also investigated. We have found that GeO₂ surface passivation can effectively suppress the dark current of a Ge PD in conjunction with gas-phase doping, and we have obtained extremely low values of Jbulk of 0.032 mA/cm² and Jsurf of 0.27 μA/cm.
authors.affiliation: Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. takenaka@mosfet.t.u-tokyo.ac.jp
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Takenaka
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Morii
authors.forename: Masakazu
authors.initials: M
authors.lastname: Sugiyama
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nakano
authors.forename: Shinichi
authors.initials: S
authors.lastname: Takagi