Surface-Structure-Controlled Heteroepitaxial Growth of 3C–SiC(001)3×2 on Si(001): Simulations and Experiments

Abstract

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 2×1 reconstruction similar to the Si(001)2×1. The addition of Si adatoms on SiC(001)2×1 results in the formation of a series of missing-dimer-row type reconstructions of h×2 where h=···, 7, 5, 3 with increasing Si adatom coverage. The most stable surface structure is SiC(001)–Si3×2 with a dangling bond density of 0.67 per SiC(001)1×1 unit cell. Analyses by transmission electron microscopy, X-ray diffraction, and electron spin resonance of 1000-Å-thick SiC(001) heteroepitaxial layers grown by MBE on miscut Si(001)–4°[110] at 1050° 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 3×2 surface reconstruction. A model involving asymmetric growth kinetics parallel and perpendicular to step edges is presented.