Observation of diamond nanocrystals in carbon films deposited during ion-assisted microwave plasma nucleation pretreatments

Diamond nanocrystals were observed in carbon films deposited by ion-assisted microwave plasma pretreatments for diamond thin films. Both selected-area electron diffraction and x-ray diffraction confirm the presence of diamond in the bias-deposited carbon films despite micro-Raman spectra and scanning electron micrographs which do not provide conclusive evidence of this carbon phase. These analyses indicate that carbon deposited by the ion-assisted nucleation process consists of a high density of nanocrystalline diamond nuclei in a nondiamond carbon matrix. Subsequent growth of these nuclei using unbiased microwave plasma chemical-vapor deposition leads to the formation of relatively smooth and thin continuous polycrystalline diamond films with small grain sizes. (C) 1995 American Institute of Physics.