Dependence of stacking fault and twin densities on deposition conditions during 3C-SiC heteroepitaxial growth on on-axis Si(0 0 1) substrates

Abstract

Single-crystal 3C-SiC epilayers were grown on on-axis Si(0 0 1) substrates by low-pressure chemical vapor deposition. The dependence of the densities of stacking faults and twins on epilayer thicknesses and growth conditions—including the reactor pressure, the substrate temperature, and the inlet gaseous composition—were investigated by a series of experiments and simulations. Simple indexes were developed to predict the planar defect densities in terms of the flux ratio of adatoms on the deposition surface. The planar defect densities were significantly reduced with increasing the epilayer thickness until continuous surfaces with {1 0 0} planes were formed at 0.7 μm. The stacking fault density was a function of the surface flux ratio of carbon adatom to atomic hydrogen, while the twin density was a function of that of silicon adatom to atomic hydrogen. Those densities were decreased almost linearly with increases in the surface flux of atomic hydrogen at fixed flux values of carbon and silicon adatoms. The surface flux of atomic hydrogen was increased as either the reactor pressure was decreased or the substrate temperature was increased.