Non-destructive pretreatment methods are generally provided for a surface of a SiC substrate with substantially no degradation of surface morphology thereon. In one particular embodiment, a molten suspension mixture (e.g., including KOH (or KOH eutectic) and a buffering agent) is applied directly onto the surface of the SiC substrate to form a treated surface thereon. An epitaxial film (e.g., SiC) can then be grown on the treated surface to achieve very high (e.g., up to and including 100%) BPD to TED conversion rate close to the epilayer/substrate interface.