Neutron Radiation Effects in Epitaxially Laterally Overgrown GaN Films
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Neutron radiation effects were studied in undoped n-GaN films grown by epitaxial lateral overgrowth (ELOG). The irradiation leads to carrier removal and introduces deep electron traps with activation energy 0.8 eV and 1 eV. After the application of doses exceeding 1017 cm−2, the material becomes semi-insulating n-type, with the Fermi level pinned near the level of the deeper electron trap. These features are similar to those previously observed for neutron irradiated undoped n-GaN prepared by standard metal–organic chemical vapor deposition (MOCVD). However, the average carrier removal rate and the deep center introduction rate in ELOG samples is about five-times lower than in MOCVD samples. Studies of electron beam induced current (EBIC) show that the changes in the concentration of charged centers are a minimum in the low-dislocation-density laterally overgrown regions and radiation-induced damage propagates inside these laterally overgrown areas from their boundary with the high-dislocation-density GaN in the windows of the ELOG mask.
Key wordsGaN ELOG neutron irradiation
The work at the Institute of Rare Metals (IRM) was supported in part by a grant from the Russian Foundation for Basic Research (RFBR grant # 05-02-08015) and ICTS (grant # 3029). The work at the University of Florida (UF) was partially supported by NSF DMR-040010.
- 1.S. Nakamura, GaN and Related Materials II, ed. S.J. Pearton (New York: Gordon and Breach Science Publishers, 1999), pp. 1–45.Google Scholar
- 2.M.S. Shur and M.A. Khan, GaN and Related Materials II, ed. S.J. Pearton (New York: Gordon and Breach Science Publishers, 1999), pp. 47–92.Google Scholar
- 14.A.Y. Polyakov, N.B. Smirnov, A.V. Govorkov, A.V. Markov, J.H. Baek, C.-R. Lee, I.-H. Lee, N.G. Kolin, I.D. Merkurisov, V.M. Boiko, and S.J. Pearton, Abstracts of European Workshop on III-Nitride Semiconductor Materials, Heraklion, Crete, Greece, September 2006 (Heraklion: Heraklion University, 2006), pp. 82–83.Google Scholar
- 17.C. Frigeri, Inst. Phys. Conf. Ser. 87: 745 (1987).Google Scholar
- 18.E.B. Yakimov, Solid State Phenomena V. 78–79, ed. H.␣Tokamage and T. Sekiguchi (Zuerich-Uetikon, Switzerland: Scitec Publications, 2001), pp. 79–85.Google Scholar
- 19.E.B.Yakimov, S.S. Borisov, and S.I. Zaitsev, Russ. Phys. Semicond., 41, 426 (2007).Google Scholar
- 21.I.-H. Lee, A.Y. Polyakov, N.B. Smirnov, A.V. Govorkov, A.V. Markov, and S.J. Pearton, Thin Solid Films, 2007, in press.Google Scholar
- 25.L.S. Berman and A.A. Lebedev, Capacitance Spectroscopy of Deep Defects in Semiconductors (Leningrad: Nauka, 1981 [in Russian]).Google Scholar