Effect of H2 dilution gas on the growth of ZrC during low pressure chemical vapor deposition in the ZrCl4–CH4–Ar system

ZrC films were deposited on a graphite substrate using low pressure chemical vapor deposition (LPCVD) in the presence of Ar + H2 dilution gas with different concentrations of H2. The H2 dilution gas influenced the properties of the ZrC film. As the H2 concentration increased, the deposition rate increased and the preferred orientation on the substrate changed. Two-dimensional, plate-shaped ZrC grew with pure Ar. In contrast, introduction of H2 gas produced ZrC films with a faceted grain, and the grain size decreased with increasing H2 concentration. Consistent with the idea that the H2 gas acted as a reactant, the changes in the properties of the ZrC film varied according to the concentration of the gas species, and this could be rationalized using thermodynamic calculations for the ZrCl4–CH4–Ar–H2 system.