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

Abstract

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.