Controlled CVD Growth of Highly ⟨111⟩-Oriented 3C-SiC

High Resolution Image Download MS PowerPoint Slide Highly ⟨111⟩-oriented 3C-SiC coatings with a distinct surface morphology consisting of hexagonally shaped pyramidal crystals were prepared by chemical vapor deposition (CVD) using silicon tetrachloride (SiCl 4 ) and toluene (C 7 H 8 ) at T ≤ 1250 °C and p tot = 10 kPa. In contrast, similar deposition conditions, with methane (CH 4 ) as the carbon precursor, resulted in randomly oriented 3C-SiC coatings with a cauliflower-like surface of SiC crystallites. No excess carbon was detected in the highly ⟨111⟩-oriented 3C-SiC samples despite the use of aromatic hydrocarbons. The difference in the preferred growth orientation of the 3C-SiC coatings deposited by using C 7 H 8 and CH 4 as the carbon precursors was explained via quantum chemical calculations of binding energies on various crystal planes. The adsorption energy of C 6 H 6 on the SiC (111) plane was 6 times higher than that on the (110) plane. On the other hand, CH 3 exhibited equally strong adsorption on both planes. This suggested that the highly ⟨111⟩-oriented 3C-SiC growth with C 7 H 8 as the carbon precursor, where both C 6 H 6 and CH 3 were considered the main active carbon-containing film forming species, was due to the highly preferred adsorption on the (111) plane, while the lower surface energy of the (110) plane controlled the growth orientation in the CH 4 process, in which only CH 3 contributed to the film deposition.