Lateral epitaxial overgrowth and reduction in defect density of 3C-SiC on patterned Si substrates

Abstract

Selective growth and reduction of defects of cubic silicon carbide (3C-SiC) crystals grown within windows and laterally over SiO2 masks patterned on Si substrates are presented. The growth has been performed via chemical vapor deposition using hexachlorodisilane and propane, as well as hexamethyldisilane. Lateral epitaxial overgrowth (LEO) was achieved at selected areas where windows are square or array of stripes. The LEO process was characterized mainly by atomic force microscopy.3C-SiC grew epitaxially on Si inside the window of SiO2 mask, and after filling up the window area, SiC grew laterally onto the SiO2 mask. The LEO begins with appearance and growth of (112) facets of 3C-SiC, and finally, the fronts of laterally overgrown SiC from the opposite sides of windows coalesce with each other. If the mask is an array of rectangular stripes, the coalescence point becomes a seam. Cathodoluminescence micrographs showed the absence of dislocations in the LEO region and the presence at the seam lines. Although many rectangular-shaped pits are observed in the area of epitaxially grown 3C-SiC, they disappeared in the LEO regions. This suggests the pits being originated upon epitaxy of 3C-SiC on Si and expanded to form rectangular shape on the final surface.