Hexamethyldisilane/propane versus silane/propane precursors: application to the growth of high-quality 3C–SiC on Si

From a comparative evaluation of hexamethyldisilane (HMDS) and silane–propane (SP) precursor systems, it is shown that HMDS needs a small addition of propane to deposit heteroepitaxial layers of 3C–SiC on Si with superior crystalline properties. In this case, propane compensates for the secondary reactions induced by hydrogen reacting with carbon. Using atmospheric pressure chemical vapour deposition conditions, the new system (HMDS–propane) demonstrates several advantages. It is safer to handle than SP and allows a higher growth rate (up to 7 µm h −1 at 1350 °C) without any degradation of the layer morphology. However, when lowering the deposition temperature, HMDS is revealed to be more stable than silane. This is in contrast to most standard beliefs but explains why a high temperature (∼1350 °C) is always necessary to grow high-quality material using HMDS.