Growth dynamics of nanocrystalline diamond films produced by microwave plasma enhanced chemical vapor deposition in methane/hydrogen/air mixture: Scaling analysis of surface morphology

• Nanocrystalline diamond films were produced by MPCVD.
• The mountain-like morphological patterns can be related to KPZ growth regime.
• The cusp-like morphological patterns are caused by non-local effects and noise.

Nanocrystalline diamond (NCD) films were produced by microwave plasma enhanced chemical vapor deposition (MPCVD) in methane/hydrogen/air plasma. The thickness of the films was varied from 0.15 to 22 μm. X-ray diffraction (XRD), Raman spectroscopy and atomic force microscopy (AFM) were used to investigate the structure and surface morphology of the films. During a short initial period of the deposition, i.e. from 2.5 min to 60 min, the growth dynamics involve relatively strong non-local effects, followed by a growth stage, which is characterized by a contribution of non-local and non-linear effects to the growth dynamics. The later regime of growth with roughness exponent α ~ 0.35–0.4 and growth exponent β ~ 0.25 can be related with the Kardar–Parisi–Zhang (KPZ) scaling regime of growth. The morphological peculiarities observed on the NCD film surface after already 2.5 min of deposition influence the morphology of the films for prolonged deposition time. Therefore, control over the size and distribution of these peculiarities by systematic variation of the deposition parameters allows to optimize the surface morphology for specific applications. The mountain-like patterns observed on the NCD films surface can be related to conformal KPZ growth regime, in contrast to the cusp-like patterns caused by non-local effects and noise.

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