Cellular structure and silicide formation in laser-irradiated metal-silicon systems

Laser irradiation of thin Co, Mo, and Pd films on single-crystalline silicon using Q-switched Nd-YAG laser pulses was shown by He backscattering to result in deep metal penetration into the Si. Evidence of the silicide formation was obtained by x-ray diffraction. Transmission electron microscopy showed the simultaneous occurrence of two types of cells with metal-rich walls: small cells of about 0.1-μm diameter, attributed to rapid solidification from a supercooled melt, and larger cells of about 1-μm diameter, attributed to convection in the melt (Bénard cells).