2.3 Growth Mechanism for 3C-SiC
To justify our arguments that the interfacial energy plays an important role in growing 3C-SiC crystal, we measured the surface tension of melts and their contact angles with 3C- and 4H-SiC crystals at high temperatures and different \(p_{N_{2}}\). Figure 4a, b are the photographs of the liquid drop at 1850 ℃ under \(p_{N_{2}}\)of 20 kPa (Melt 4) on 3C-(111) and semi-insulating 4H-SiC (0001) crystals, respectively, indicating the contact angles are 40.38° ± 0.64° and 45.55° ± 0.07°. The measured surface tension is \(\sigma_{Melt\ 4}=\)761.24 ± 27.83 mN/m at the same temperature (Figure 4c and Figures S14-15). According to Young’s equation:
\(\sigma_{SiC/Melt\ }=\sigma_{\text{SiC}}-\sigma_{\text{Melt\ }}\cos\theta\)(3)
where \(\sigma_{SiC/Melt\ }\) is the interfacial energy between SiC and melt, \(\sigma_{\text{SiC}}\) the surface energy of SiC,\(\sigma_{\text{Melt\ }}\) surface tension of melt and \(\theta\)contact angle between SiC and melt.