A comparative study of the growth dynamics and tribological properties of nanocrystalline diamond films deposited on the (110) single crystal diamond and Si(100) substrates

摘要

Nanocrystalline diamond (NCD) films were grown on the High Pressure High Temperature (HPHT) (110) single crystal (SC) diamond substrates by Microwave Plasma Enhanced Chemical Vapor Deposition (MPCVD) in methane/hydrogen/nitrogen plasma. The thickness of the films was varied between 2.2 and 22.5 mu m. The cauliflower-like surface morphology was observed by means of Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). The scaling behavior of NCD films growth was investigated. The relatively high value of the roughness exponent alpha(s) = 1.5-1.6 was found indicating anomalous scaling. Therefore, shadowing and diffusional instabilities can affect the film growth. The tribological properties of the NCD films deposited on the SC(110) diamond were compared with the NCD films prepared on the Si(100) substrates. Both types of specimens were tested under similar Hertzian contact pressure. The lower wear volume losses were observed on the NCD/SC(110) specimens. Therefore, the influence of substrate and substrate/film interface properties on the tribological behavior of the NCD films grown on Si(100) can be expected to cause NCD films deflection.