Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
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Characterization of epitaxial layers on beta-gallium oxide single crystals grown by EFG method as a function of different crystal faces and off-angle

EFG 법으로 성장시킨 β-Ga2O3 단결정의 다양한 결정면, off-angle에 따른 epitaxial layer의 특성 분석

  • Min-Ji Chae (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Sun-Yeong Seo (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Hui-Yeon Jang (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • So-Min Shin (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Dae-Uk Kim (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Yun-Jin Kim (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Mi-Seon Park (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Gwang-Hee Jung (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Jin-Ki Kang (AXEL) ;
  • Hae-Yong Lee (LumiGNtech Co, Ltd) ;
  • Won-Jae Lee (Department of Advanced Materials Engineering, Dong-Eui University)
  • Received : 2024.07.11
  • Accepted : 2024.07.26
  • Published : 2024.08.31
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Abstract

β-Ga2O3 is a representative ultra-wide bandgap (UWBG) semiconductor that has attracted much attention for power device applications due to its wide-bandgap of 4.9 eV and high-breakdown voltage of 8 MV/cm. In addition, because solution growth is possible, it has advantages such as fast growth rate and lower production cost compared to SiC and GaN [1-2]. In this study, we have successfully grown Si-doped 10 mm thick Si-doped β-Ga2O3 single crystals by the EFG (Edge-defined Film-fed Growth) method. The growth direction and growth principal plane were set to [010] / (010), respectively, and the growth speed was 7~20 mm/h. The as-grown β-Ga2O3 single crystal was cut into various crystal planes (001, 100, ${\bar{2}}01$) and off-angles (1o, 3o, 4o), and then surface processed. After processed, the homoepitaxial layer was grown on the epi-ready substrate using the HVPE (Halide vapor phase epitaxy) method. The processed samples and the epi-layer grown samples were analyzed by XRD, AFM, OM, and Etching to compare the surface properties according to the crystal plane and off-angle.

β-Ga2O3는 4.9 eV의 넓은 밴드갭과 8 MV/cm의 높은 항복전압으로 전력 소자 응용 분야에서 많은 관심을 받고 있는 대표적인 UWBG(Ultra-wide Band-gap) 반도체이다. 또한 용액 성장이 가능하기 때문에 SiC, GaN에 비해 성장 속도가 빠르고 생산 비용이 저렴하다는 장점이 있다[1,2]. 본 연구에서는 EFG(Edge-defined Film-fed Growth) 법을 통해 Si 도핑 된 β-Ga2O3 단결정을 성장시키는 데에 성공하였다. 성장 방향과 성장 주 면은 각각 [010] / (001)로 설정하였으며 성장속도는 7~20 mm/h이다. 성장시킨 β-Ga2O3 단결정은 다양한 결정 면 방향(001, 100, ${\bar{2}}01$)과 off-angle(1o, 3o, 4o)에 따라 절단하여 표면 가공을 진행하였고, 가공 후 HVPE(Halide vapor phase epitaxy) 법을 이용해 epi-ready 기판 위에 homoepitaxial 층을 성장시켰다. 가공 후의 샘플과 epi-layer를 성장시킨 샘플을 XRD, AFM, OM, Etching 등의 분석을 통해 결정면과 off-angle에 따른 표면 특성을 비교하였다.

Keywords

Acknowledgement

이 연구는 2024년 교육부의 재원으로 한국기초과학지원연구원 국가연구시설장비진흥센터의 지원(No. 2019R1A6C1010045)과 2024년 정부(과학기술정보통신부)의 재원으로 한국연구재단-나노 및 소재기술개발사업의 지원(2021M3H4A3A01061784)과 2024년 정부(산업통상자원부)의 재원으로 한국산업기술진흥원의 지원(P0012451, 2024년 산업혁신인재성장지원사업)을 받아 수행된 연구임.

References

  1. M. Higashiwaki and G.H. Jessen, "Guest editorial: The dawn of gallium oxide microelectronics", Appl. Phys. Lett. 112 (2018) 060401.
  2. S. Zhang, X. Lian, Y. Ma, W. Liu, Y. Zhang, Y. Xu and H. Cheng, "Growth and characterization of 2-inch high quality β-Ga2O3 single crystals grown by EFG method", J. Semicond. 39 (2018) 083003.
  3. J.B. Varley, H. Peelaers, A. Janotti and C.G. Van de Walle, "Hydrogenated cation vacancies in semiconducting oxides: Origin of doping asymmetry", J. Phys.: Condens. Matter 23 (2011) 334212.
  4. K. Sasaki, A. Kuramata, T. Masui, E. Goto and S. Yamakoshi, "Device-quality β-Ga2O3 epitaxial films fabricated by ozone molecular beam epitaxy", Appl. Phys. Express 5 (2012) 035502.
  5. A. Kuramata, K. Koshi, S. Watanabe, Y. Yamaoka, T. Masui and S. Yamakoshi, "High-quality β-Ga2O3 single crystals grown by edge-defined film-fed growth", Jpn. J. Appl. Phys. 55 (2016) 1202A2.
  6. H.W. Xue, H. Qiming, G.Z. Jian and S. Long, "An overview of the ultrawide bandgap Ga2O3 semiconductor-based Schottky barrier diode for power electronics application", Nanoscale Research Letters 13 (2018) 1.
  7. M. Higashiwaki and S. Fujita, editors, Gallium Oxide: Materials Properties, Crystal Growth, and Devices (Springer International Publishing, Cham, 2020).
  8. P. Vogt and O. Bierwagen, "Reaction kinetics and growth window for plasma-assisted molecular beam epitaxy of Ga2O3: Incorporation of Ga vs. Ga2O desorption", Appl. Phys. Lett. 108 (2016) 072101.
  9. P. Vogt and O. Bierwagen, "Kinetics versus thermodynamics of the metal incorporation in molecular beam epitaxy of (InxGa1-x)2O3", APL Mater. 4 (2016) 086112.
  10. K. Sasaki, M. Higashiwaki, A. Kuramata, T. Masui and S. Yamakoshi, "Growth temperature dependences of structural and electrical properties of Ga2O3 epitaxial films grown on β-Ga2O3 (010) substrates by molecular beam epitaxy", J. Cryst. Growth 392 (2014) 30.
  11. G. Wagner, M. Baldini, D. Gogova, M. Schmidbauer, R. Schewski, M. Albrecht, Z. Galazka, D. Klimm and R. Fornari, "Homoepitaxial growth of β-Ga2O3 layers by metal-organic vapor phase epitaxy", Physica Status Solidi (a) 211 (2014) 27.
  12. X. Du, W. Mi, C. Luan, Z. Li, C. Xia and J. Ma, "Characterization of homoepitaxial β-Ga2O3 films prepared by metal-organic chemical vapor deposition", J. Cryst. Growth 404 (2014) 75.
  13. M. Orita, H. Ohta, M. Hirano and H. Hosono, "Deep-ultraviolet transparent conductive β-Ga2O3 thin films", Appl. Phys. Lett. 77 (2000) 4166.
  14. T. Oshima, T. Nakazono, A. Mukai and A. Ohtomo, "Epitaxial growth of γ-Ga2O3 films by mist chemical vapor deposition", J. Cryst. Growth 359 (2012) 60. https://doi.org/10.1016/j.jcrysgro.2012.08.025
  15. H. Murakami, K. Nomura, K. Goto, K. Sasaki, K. Kawara, Q.T. Thieu, R. Togashi, Y. Kumagai, M. Higashiwaki, A. Kuramata, S. Yamakoshi, B. Monemar and A. Koukitu, "Homoepitaxial growth of β-Ga2O3 layers by halide vapor phase epitaxy", Appl. Phys. Express 8 (2014) 015503.
  16. Y. Oshima, E.G. Villora and K. Shimamura, "Halide vapor phase epitaxy of twin-free α-Ga2O3 on sapphire (0001) substrates", Appl. Phys. Express 8 (2015) 055501. https://doi.org/10.7567/APEX.8.055501
  17. Y. Oshima, E.G. Vίllora and K. Shimamura, "Quasi-heteroepitaxial growth of β-Ga2O3 on off-angled sapphire (0001) substrates by halide vapor phase epitaxy", J. Cryst. Growth 410 (2015) 53.
  18. K. Goto, H. Murakami, A. Kuramata, S. Yamakoshi, M. Higashiwaki and Y. Kumagai, "Effect of substrate orientation on homoepitaxial growth of β-Ga2O3 by halide vapor phase epitaxy", Appl. Phys. Lett. 120 (2022) 102102.
  19. K. Ogawa, N. Ogawa, R. Kosaka, T. Isshiki, T. Aiso, M. Iyoki, Y.Z. Yao and Y. Ishikawa, "AFM observation of etch-pit shapes on β-Ga2O3 (001) surface formed by molten alkali etching," MSF 1004 (2020) 512.
  20. S. Sdoeung, K. Sasaki, K. Kawasaki, J. Hirabayashi, A. Kuramata and M. Kasu, "Characterization of dislocation of halide vapor phase epitaxial (001) β-Ga2O3 by ultrahigh sensitive emission microscopy and synchrotron X-ray topography and its influence on Schottky barrier diodes", Jpn. J. Appl. Phys. 62(SF) (2023) SF1001.
  21. A.A. Zarichny, P.N. Butenko and M.E. Boiko, "The analysis of the etch pits parameters in the (${\bar{2}}01$) plane of the β-Ga2O3 substrate crystals", Materials Physics and Mechanics 51 (2023) 174.
  22. Y. Liu, Z. Jin, L. Li, N. Xia, H. Zhuang and D. Yang, "Two types of etching pits in (100) β-Ga2O3 single crystals grown by casting method", Micro and Nanostructures 176 (2023) 207541.