Correlation of the crystal structural and microstructural effects of the interfacial processes between gold and GaAs

The solid state interfacial reaction between gold and GaAs was found to result in small surface microstructural changes, whereas melting of the reaction product (tentatively identified as AuGa) and subsequent solidification to form the β phase resulted in aligned rectangular protrusions with sharp corners. The rectangular protrusions were found to be much finer in scale after heating in a vacuum than after heating in argon at 1 atm. High cooling rates (e.g. 40°C min^-1) during solidification resulted in the formation of both rectangular protrusions and irregularly shaped protrusions with jagged boundaries and topography. The irregular protrusions were associated with a phase tentatively identified as Au₂Ga. Rapid cooling at about 600°C min^-1 during solidification resulted in the formation of the gold-rich terminal solid solution (α phase) which appeared as aligned rectangular protrusions with rounded corners.