Structural properties of As-rich GaAs grown by molecular beam epitaxy at low temperatures

• Published in: Applied physics letters 1989-05, Vol.54 (19), p.1881-1883
• Main Authors: KAMINSKA, M, LILIENTAL-WEBER, Z, WEBER, E. R, GEORGE, T, KORTRIGHT, J. B, SMITH, F. W, TSAUR, B.-Y, CALAWA, A. R
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states; Exact sciences and technology; Impurity and defect levels; Physics
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.101229

GaAs layers grown by molecular beam epitaxy (MBE) at substrate temperatures between 200 and 300 °C were studied using transmission electron microscopy (TEM), x-ray diffraction, and electron paramagnetic resonance (EPR) techniques. High-resolution TEM cross-sectional images showed a high degree of crystalline perfection of these layers. For a layer grown at 200 °C and unannealed, x-ray diffraction revealed a 0.1% increase in the lattice parameter in comparison with bulk GaAs. For the same layer, EPR detected arsenic antisite defects with a concentration as high as 5×1018 cm−3. This is the first observation of antisite defects in MBE-grown GaAs. These results are related to off-stoichiometric, strongly As-rich growth, possible only at such low temperatures. These findings are of relevance to the specific electrical properties of low-temperature MBE-grown GaAs layers.