Abstract
Raman scattering measurements on high-resistivity layers of GaAs grown by molecular beam epitaxy at low temperature are presented. Several defect-related features are ob-served, including two peaks attributed to quasi-localized vibrational modes of point de-fects, one with a frequency of 223 cm−1 similar to a mode previously observed in elec-tron-irradiated GaAs, and the other with a frequency of 47 cm−1 similar to a mode observed in ion-implanted GaAs. We suggest that these are due to arsenic interstitials and gallium vacancies, respectively. We also observe peaks at 200 and 258 cm−1, which we believe may be due to vibrational modes in small clusters of arsenic. The 223 cm−1 mode is the only defect-related mode still observed after a 10-min annealing treatment at 600° C, although it is significantly broader and has different symmetry from the 223 cm−1 mode in the unannealed material. This indicates that the 223 cm−1 mode in the annealed material is due, at least in part, to a defect other than the arsenic interstitial.
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Berg, R.S., Mavalvala, N., Steinberg, T. et al. Raman study of defects in a GaAs buffer layer grown by low-temperature molecular beam epitaxy. J. Electron. Mater. 19, 1323–1330 (1990). https://doi.org/10.1007/BF02673349
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DOI: https://doi.org/10.1007/BF02673349