Published online by Cambridge University Press: 25 February 2011
The thermal stability of PtAl thin films on GaAs substrates has been studied using transmission electron microscopy and Auger electron spectroscopy. The PtAl thin films were formed by sequential deposition of discrete Pt and Al layers on GaAs by e-beam evaporation followed by subsequent annealing processes. Interfacial reactions in the Al/Pt/GaAs system proceed in two stages. Upon low temperature annealing Pt and GaAs react to form PtGa and PtAs2. Further high temperature annealing causes PtGa, PtAs2 and Al to react together producing the desired PtAl on GaAs. We observed solid-phase epitaxial regrowth of GaAs during the second stage of reaction. The PtAl/GaAs interface is determined to be thermally stable during an 800°C/30 min. anneal, while remaining morphologically uniform on GaAs.