Surface-structure-controlled heteroepitaxial growth of 3C-SiC(001)3x2 on Si(001): Simulations and experiments

Mechanistic reaction paths for the heteroepitaxial growth of 3C-SiC on carbonized Si(001) were investigated using a combination of molecular dynamics (MD) simulations and molecular beam epitaxy (MBE) experiments. The stable Si-terminated 3C-SiC(001) surface was found by MD to exhibit a 2 x I reconstruction similar to the Si(001)2 x 1. The addition of Si adatoms on SiC(001)2 x 1 results in the formation of a series of missing-dimerrow type reconstructions of h x 2 where h = ..., 7, 5, 3 with increasing Si adatom coverage. The most stable surface structure is SiC(001)-Si3 x 2 with a dangling bond density of 0.67 per SiC(001)1 x 1 unit cell. Analyses by transmission electron microscopy, X-ray diffraction, and electron spin resonance of 1000-Angstrom-thick Sic(001) heteroepitaxial layers grown by MBE on miscut Si(001)-4 degrees[110] at 1050 degrees C as a function of incident C/Si flux ratio J(C)/J(Si) showed that the highest quality layers were obtained by surface-structure-controlled epitaxy in which in-situ reflection high-energy electron diffraction was used as a feedback signal to adjust J(C)/J(Si), during growth to maintain a 3 x 2 surface reconstruction. A model involving asymmetric growth kinetics parallel and perpendicular to step edges is presented.