Unveiling the magic of H2S on the CVD-Al2O3 coating

The role of H 2 S in the mechanism of CVD-Al 2 O 3 coating was investigated by measuring particles suspended in the gas phase with an optical particle counter. H 2 S doping, of the CVD-Al 2 O 3 process improves the homogeneity of thickness and growth rate of the Al 2 O 3 layer. The number of particles produced in the reactor whose size was larger than 200 nm was dramatically reduced by H 2 S doping. The effect of H 2 S doping appears to be a reduction of the size of Al 2 O 3 particles present in the reactor. These smaller particles have a greater mobility, which will allow them to arrive at the surface, regardless of the shape or arrangement of the substrate inside the reactor.