Effect of the Si droplet size on the VLS growth mechanism of SiC homoepitaxial layers

The Vapour-Liquid-Solid (VLS) mechanism is a promising way to reach fast growth regime for temperatures lower than sublimation epitaxy or conventional LPE. We have investigated the homoepitaxial growth on off-axis 4H-SiC substrates from such a mechanism in a vertical cold wall CVD reactor. The experiments involved either Si wafers melting and propane as feeding vapour phase or highly Si rich CVD like conditions with silane and propane. The effect of the silicon droplets size on the VLS mechanism was studied. With the CVD like conditions, growth rate up to 35 mum/h at 1600degreesC is demonstrated with a bunched steps and terraces structure, homogeneous on the whole wafer size.