Carrier Trapping by Vacancy-Type Defects in Mg-Implanted GaN Studied Using Monoenergetic Positron Beams

Akira Uedono, Shinya Takashima, Masaharu Edo, Katsunori Ueno, Hideaki Matsuyama, Werner Egger, Tönjes Koschine, Christoph Hugenschmidt, Marcel Dickmann, Kazunobu Kojima, Shigefusa F. Chichibu, Shoji Ishibashi

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Vacancy-type defects in Mg-implanted GaN are probed using monoenergetic positron beams. Mg+ ions are implanted to provide a 500-nm-deep box profile with Mg concentrations, [Mg], of 1 × 1017–1 × 1019 cm−3 at room temperature. In the as-implanted samples, the major defect species is a complex of a Ga vacancy (VGa) and a nitrogen vacancy (VN). After annealing above 1000 °C, the major defect species is changed to vacancy clusters due to vacancy agglomeration. This agglomeration is suppressed, and the agglomeration onset temperature is decreased with a decreasing [Mg]. For samples with [Mg] ≥ 1 × 1018 cm−3, the trapping rate of positrons by vacancy-type defects decrease after annealing above 1100–1200 °C. This decreases is attributed to the change in the defect charge states from neutral to positive due to a downward shift of the Fermi level. The carrier trapping/detrapping properties of the vacancy-type defects and their time dependences are also revealed.

Original languageEnglish
Article number1700521
JournalPhysica Status Solidi (B) Basic Research
Volume255
Issue number4
DOIs
Publication statusPublished - 2018 Apr

Keywords

  • GaN
  • defects
  • ion implantation
  • positron annihilation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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    Uedono, A., Takashima, S., Edo, M., Ueno, K., Matsuyama, H., Egger, W., Koschine, T., Hugenschmidt, C., Dickmann, M., Kojima, K., Chichibu, S. F., & Ishibashi, S. (2018). Carrier Trapping by Vacancy-Type Defects in Mg-Implanted GaN Studied Using Monoenergetic Positron Beams. Physica Status Solidi (B) Basic Research, 255(4), [1700521]. https://doi.org/10.1002/pssb.201700521