Effect of Nucleation Density on the Morphology of Diamond Thin Films

Abstract

The morphology of diamond films deposited in the substrate temperature range of 550° C to 750° C by microwave plasma enhanced chemical vapor deposition (MPECVD) has been investigated as a function of the nucleation density. Nucleation density can be controlled in the range of 1.5×10⁷ to 1.0×10¹⁰ nuclei/cm² by varying the ultrasonic pretreatment time and the particle size of diamond powders. At high nucleation density, the thin films consist of well-faceted grains for all deposition times. Low nucleation density leads to cauliflower-like morphology for the initial deposition time, which develops into the well-faceted {100} grain with increasing deposition time. These results indicate that higher nucleation density reduces the time required to develop well-faceted diamond grains. Therefore, we can conclude that the final surface morphology of the diamond films is identical regardless of the nucleation density, after long growth time.