Change from micrometre to nanometre size for diamond grains by plasma chemical vapourdeposition

Abstract

Nanocrystalline diamond (NCD) films were deposited usingCH4 and H2 gas mixtures by the electron assisted chemical vapour deposition (EACVD) method at 640 and400 °C, and microcrystalline diamond film was simultaneously synthesized at890 °C. The size of NCD was estimated as about 8–100 nm according to electron micrographs andthe full width at half maximum of diamond features of x-ray diffraction spectra. Wehave investigated the local gas environments where diamond films were depositedusing a quadrupole mass spectrometer. It shows that the growth temperature andlocal gas environment are two important factors influencing diamond grain size.