Simulation and experimental research on the substrate temperature distribution in HFCVD diamond film growth on the inner hole surface

The substrate temperature distribution in HFCVD diamond film growth on the inner hole surface is simulated by the finite volume method in the present study, adopting a detailed 3-D computational model agreeing with the actual reactor. Firstly, the influences of several key deposition parameters are studied by the control variable method, including the cooling condition C, the filament temperature Tf, the filament diameter d and the substrate aperture D. Afterwards, the substrate temperatures in the actual reactor are measured. Deviations between the simulated and measured temperature values are all less than 5%, and the substrate temperature distribution trends in the measurement results are well coincident with those in the simulation results. Furthermore, corresponding deposition experiments are also conducted, the results of which can further validate the correctness of the simulations. Finally, the optimized deposition parameters are used to deposit diamond films on the inner hole surfaces of the WC–Co substrates with apertures of either 6 mm or 8 mm. The characterizations show that homogeneous diamond films with fine-faceted diamond crystals are obtained, indicating that this deposition parameter optimization method is feasible for fabricating high-quality diamond films on the inner hole surfaces.

► A novel 3-D model is adopted to calculate the substrate temperature distributions. ► Simulation results are tested on the measured data for various HFCVD parameters. ► Deposition parameters are optimized based on the simulations and measurements. ► Diamond films with high quality are obtained with the optimized parameters.