Interfacial chemical reactions of Au with 3-5 compound semiconductors

In order to understand the chemistry at the interface between two solids, one must first know the thermodynamic stability of the bulk materials with respect to each other. When the system involves three elements, such as a gold thin film on a 3-5 compound-semiconductor substrate, a ternary phase diagram must be determined. The solidus portions of the nine Gold-3-5 (3 = Aluminum, Gallium, Indium; 5 = Phosphorus, Arsenic, Antimony) ternary phase diagrams at 298K have been determined. Many of the solid-phase equilibria were found by calculating reaction enthalpies directly from thermochemical data available in the literature. However, for some systems, no data were available, and the required data were estimated or experiments were performed to determine the tie lines through the ternaries. Ideal conditions (no vapor-phase formation or significant mutual solid solubility) were assumed. The resulting phase diagrams may be used to determine, in systems that are effectively closed, which metal/semiconductor interfaces in the Au-3-5 family are stable and which are not.