Formation of epitaxial graphene (EG) on 3C-SiC films heteroepitaxially grown on Si substrates, otherwise known as graphene-on-silicon (GOS) technology, has a high potential in future nanocarbon-based electronics. The EG's quality in GOS however remains mediocre due mostly to the high density of crystal defects in the 3C-SiC/Si films caused by the large (~ 20%) lattice-mismatch between Si and 3C-SiC crystals. Resultant Si out-diffusion along the planar defects during the higherature (~ 1525 K) graphitization annealing can also account for the degradation. Here we propose a two-step growth technique that consists of seeding of rotated 3C-SiC(-1-1-1) crystallites on the Si(110) substrate, conducted in the higherature-low-pressure regime, followed by a rapid growth of SiC films in the lowerature-high-pressure regime. We succeeded in forming an almost lattice-relaxed 3C-SiC(-1-1-1) film on Si(110), having a sufficient thickness (~ 200 nm) that we believe is able to suppress the Si out-diffusion during graphitization. A graphitization annealing applied to this epi-film yields an EG, whose domain size is increased by 60% as compared to that of conventional GOS films.
- Epitaxial graphene
- Gas-source MBE