Effect of Al addition to Si-Ni flux on pulsed laser deposition of SiC thin films

Abstract

The effects of Al addition to SiNi flux on the flux-mediated pulsed laser deposition of SiC thin films were investigated. A small amount of 3 at.% Al addition was found to cause the dominant growth of a polytype of 6HSiC (0001) at an early stage of the deposition on a 4HSiC (0001) on-axis substrate even at a low growth temperature of 1160°C, at which a single polytype of 3CSiC (111) film is thermodynamically favored. The direct observation of the interface between SiC and SiNi based flux with our originally developed high-vacuum laser microscope revealed that the dissolution behavior of SiC into SiNiAl flux becomes milder than that before Al addition to SiNi flux. This feature is not inconsistent with the commonly accepted surface flattening effect of Al addition to the SiCr solvent in the flux growth of SiC bulk single crystals, and might be partially responsible for the initial preference of the 6HSiC (0001) polytype growth.