Published online by Cambridge University Press: 26 February 2011
The structure of Al/GaAs interfaces was investigated by high resolution electron microscopy. The Al layers Were deposited in a molecular beam epitaxy chamber with a vacuum base pressure of <1×10∼8 Pa. The GaAs substrate temperature varied during Al deposition from -30°C to 400°C. Deposition of Al on cold substrates £25°C resulted in epitaxial growth of (001) Al on (001) GaAs. Droplets of Ga were observed in samples with the substrate temperature at -30°C (1×2) and 0°C (c(2×8)). Postannealing of the last sample caused formation of the AlGaAs phase. Deposition of Al on hot substrates (150°C and 400°C) resulted in the formation of the AlGaAs phase, which separated (110) oriented Al from (001)GaAs.