In situ investigation of stage of the formation of eutectic alloys in Si–Au and Si–Al systems

Abstract

The in situ electron microscopic investigations of the formation of eutectic alloys in the systems: amorphous Si/particle Au, amorphous Si/particle Al showed that the formation of eutectics is preceded by metal diffusion into amorphous silicon with the formation of metastable amorphous metal silicide. Supersaturation and decomposition of the metastable amorphous metal silicide leads to the evolution of polycrystal silicon. Morphological characteristics of the liquid eutectic formation in the systems crystalline (100)Si/particle Au and crystalline (100)Si/particle Al are similar to the well known morphological characteristics of the formation of etch pits in crystals. For the systems crystalline (100)Si/particle Au, an oriented formation of the liquid eutectic alloy is observed. The growth of the eutectic melt during the annealing of the system crystalline (100)Si/particle Al takes place isotropically. The crystallization of liquid eutectic alloy leads to topotaxial evolution of gold silicide islands at the interface: crystal eutectics–single crystal silicon.