Interface analysis of CVD diamond on TiN surfaces

Abstract

We prepared polycrystalline diamond thin films on smooth silicon substrates with the help of a titanium nitride (TiN) buffer layer. TiN layers of different thickness were deposited first on crystalline silicon substrates with mirror finish. The TiN layers were placed by physical vapor deposition (PVD) assisted by direct current reactive magnetron sputtering. Later, diamond thin films were grown by hot filament chemical vapor deposition (HF-CVD). Scanning electron microscopy observations show a notable increase in the size of diamond particles on the substrates with the TiN buffer layer, as opposed to the plain, only scratched substrates. The diamond films were characterized by high-resolution transmission electron microscopy (HRTEM), electron energy loss (EELS) and energy dispersive spectroscopies (EDS). A buffer layer ∼0.8 nm thick is observed between the diamond particles and the TiN layer. EDS experiments reveal a carbon nitride compound at the interphase. There is no evidence of degradation (cracking, delamination, etc.) of the TiN layers for thickness below 0.5 μm.