Conformal and superconformal chemical vapor deposition of silicon carbide coatings

Abstract

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 submicrometer scale vias and trenches, are tested here 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 accomplished at deposition temperatures between 950 and 1000 °C with precursor partial pressure higher than 20 Pa and an optional minor addition of 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. With the slower kinetics and the site blocking from precursor saturation leading the growth to nearly conformal and the possibly preferential inhibition effect near the opening than at the depth, a superconformal SiC coating with 2.6 times higher thickness at the bottom compared to the top of a 1 mm trench was achieved.