A substrate and method for growing a semi-conductive crystal on an alloy film such as (AIN)x(SiC)(1-x) without any buffer layer is disclosed. The (AIN)x(SiC)(1-x) alloy film can be formed on a SiC substrate by a vapor deposition process using AlN and SiC powder as starting materials. The (AIN)x(SiC)(1-x) alloy film provides a better lattice match for GaN or SiC epitaxial growth and reduces defects in epitaxially grown GaN with better lattice match and chemistry.