Neutron Radiation Effects in Epitaxially Laterally Overgrown GaN Films

• Published in: Journal of electronic materials 2007-10, Vol.36 (10), p.1320-1325
• Main Authors: Polyakov, A. Y., Smirnov, N. B., Govorkov, A. V., Markov, A. V., Yakimov, E. B., Vergeles, P. S., Kolin, N. G., Merkurisov, D. I., Boiko, V. M., Lee, In-Hwan, Lee, Cheul-Ro, Pearton, S. J.
• Format: Article
• Language: English
• Subjects: Gallium nitride epitaxy; Neutrons; Radiation; Semiconductors
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-007-0203-8

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 10^sup 17^ cm^sup -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. [PUBLICATION ABSTRACT]