Control of vacancy-type defects in Mg implanted GaN studied by positron annihilation spectroscopy

Akira Uedono, Marcel Dickmann, Werner Egger, Christoph Hugenschmidt, Shoji Ishibashi, Shigefusa F. Chichibu

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Vacancy-type defects in Mg-implanted GaN were probed using monoenergetic positron beams. Mg+ ions were implanted to provide box profiles with Mg concentrations [Mg] of 1017-1019 cm-3. For as-implanted samples, the major defect species was determined to be Ga-vacancy (VGa) related defects such as divacancy (VGaVN) and/or their complexes with impurities. For Mg-implanted samples, an agglomeration of vacancies started at 800-1000°C annealing, leading to the formation of vacancy clusters such as (VGaVN)3. For the sample with [Mg]=1019 cm-3, the trapping rate of positrons to the vacancies decreased with increasing annealing temperature (≥1100°C), which was attributed to the change in the charge state of vacancy-type defects from neutral to positive (or negative to neutral) due to the activation of Mg. For Mg- and H-implanted samples, the hydrogenation of vacancy-type defects started after 800°C annealing. Comparing with the annealing behavior of defects for the samples without H-implantation, the clustering of vacancy-type defects was suppressed, which can be attributed to the interaction between Mg, H, and vacancies.

Original languageEnglish
Title of host publicationGallium Nitride Materials and Devices XV
EditorsHiroshi Fujioka, Hadis Morkoc, Ulrich T. Schwarz
ISBN (Electronic)9781510633230
Publication statusPublished - 2020
EventGallium Nitride Materials and Devices XV 2020 - San Francisco, United States
Duration: 2020 Feb 42020 Feb 6

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceGallium Nitride Materials and Devices XV 2020
Country/TerritoryUnited States
CitySan Francisco


  • Defect
  • Doping
  • GaN
  • Ion implantation
  • Positron annihilation
  • Vacancy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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