Conformal and superconformal chemical vapor deposition of silicon carbide coatings

The approaches to conformal and superconformal deposition developed by Abelson and Girolami for a low temperature, low pressure chemical vapor deposition (CVD) setting relevant for electronic materials in micrometer or sub-micrometer scale vias and trenches, are here tested in a high temperature, moderate pressure CVD setting relevant for hard coatings in millimeter scale trenches. Conformal and superconformal deposition of polycrystalline silicon carbide (SiC) can be deposited by decreasing the deposition temperature, increasing the precursor partial pressure, or adding HCl as a growth inhibitor. The conformal deposition at low temperatures is ascribed to slower kinetics of the precursor consumption along the trench depth, whereas the impact of high precursor partial pressure and addition of inhibitor is attributable to surface-site blocking. By combining these three deposition conditions, a superconformal SiC coating with 2.6 times higher thickness at the bottom compared to the top of a 1 mm trench was achieved.