In-situ dynamic high-resolution transmission electron microscopy: application to Pt/GaAs interfacial reactions

In-situ annealing high-resolution transmission electron microscopy (HRTEM) is a powerful technique for the observation of dynamic events in materials at the atomic scale. This paper discusses its use, and applies it to the study of the interfacial reactions in the Pt/GaAs system. We observed that initially a solid-state amorphization process occurs, by the dominant diffusion of Pt to the GaAs. The correlation of the kinetic data with the microstructural changes reveals that the diffusion kinetics are changed after the transformation of the amorphous phase to a crystalline product. During the high-temperature reaction which produces crystalline platinum gallide and platinum di-arsenide, we observed that GaAs substrate is dissociated in a layer-by-layer manner via a ledge mechanism. The whole reaction process and kinetic data are consistent with those of parallel ex-situ annealing experiments.