Uniform growth of SiC single crystal thin films via a metal-Si alloy flux by vapour-liquid-solid pulsed laser deposition: The possible existence of a precursor liquid flux film

For their use as next generation power semiconductors, new vapor growth processes for SiC single crystal films have been highly demanded, among which is the vapor-liquid-solid (VLS) growth with a metal-Si flux. If the metal-Si flux liquid were highly wettable on SiC, a thinner flux liquid layer would be favored for a higher growth rate in the VLS process. We demonstrated that a thin NiSi₂ layer, even as small as 150 nm in thickness to form liquid droplets, could work effectively as a flux in the pulsed laser deposition (PLD)-based VLS process for the uniform growth of high-quality 3C-SiC (111) films on 4H-SiC (0001). In situ direct observation of the interface between the flux and single crystal SiC using a laser microscope strongly implied the existence of a precursor liquid flux film spreading between the NiSi₂ droplets that can have a similar role in the flux growth process, resulting in significant improvements in the surface morphology, crystallinity as well as stoichiometry of SiC films.