Effects of Low-Temperature GeSn Buffer Layers on Sn Surface Segregation During GeSn Epitaxial Growth

  • Takahiro TsukamotoEmail author
  • Nobumitsu Hirose
  • Akifumi Kasamatsu
  • Toshiaki Matsui
  • Yoshiyuki Suda
Original Article - Electronics, Magnetics and Photonics


We investigate the effects of the low-temperature (LT) GeSn buffer layers on Sn surface segregation during the growth of the additional GeSn layers. Sn surface segregation was observed in the GeSn layers formed on Si substrates at the growth temperature of 300 °C. However, there was no Sn surface segregation in the GeSn layers grown at 300 °C on the LT GeSn buffer layers formed at 225 °C. The Sn surface segregation was limited by the effects of the LT buffer layers. Crystallinity of the GeSn layers grown at 300 °C on the LT GeSn buffer layers was investigated by Raman spectroscopy. The full width at half maximum of the Ge–Ge Raman spectrum obtained from the GeSn layers was about 3.1 cm−1, which means that the formed GeSn layers have excellent crystallinity. We have successfully demonstrated that the LT GeSn buffer layers can limit the Sn surface segregation, which increases the growth temperature and improves crystallinity of the GeSn layers.

Graphic Abstract


GeSn Sputter epitaxy Buffer layer Sn segregation Raman 



This research and development work was supported by the MIC/SCOPE #165103005. This work was partly carried out in the Advanced ICT Devices Lab in NICT.


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Copyright information

© The Korean Institute of Metals and Materials 2019

Authors and Affiliations

  1. 1.The University of Electro-CommunicationsChofuJapan
  2. 2.National Institute of Information and Communications TechnologyKoganeiJapan
  3. 3.Tokyo University of Agriculture and TechnologyKoganeiJapan

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