Effect of hydrogen flow on microtwins in 3C-SiC epitaxial films by laser chemical vapor deposition

Epitaxial 3C-SiC films were fabricated on Si(001) by laser chemical vapor deposition using hexamethyldisilane as the precursor source and H-2 as the dilution gas. The effect of the H-2 flow rate on the density of microtwins in 3C-SiC films was investigated. Crystallographic defects were mainly composed of {111} twins, which tilted 15.8 degrees to the surface of the substrate and refer to the multiple twins mirrored by the first-order twins; these defects were characterized by pole figure. With the flow rate of H-2 increased from 1.0 to 3.0 slm (standard liter per minute), the relative twin density first decreased from 24.0 to 1.2 and then increased to 16.0. The mechanism of the formation and elimination of the defects is also discussed.