Crack and defect formation in diamond films

In this paper, mechanisms of defect and crack initiation in a diamond film prepared at substrate temperatures are investigated using direct current plasma chemical vapor deposition method. The study is by way of X ray diffraction (XRD), optical microscope (OM), and scanning electron microscopy (SEM) and reveals that initiation of defects and cracks during the growth of diamond films depends strongly on substrate temperature. The defects and impurities formed in high substrate temperatures include mainly residual stresses, and non-diamond phase such as graphite and amorphous carbon, which result in forming crack and microscopic hole in diamond film. X ray diffraction, optical microscope and SEM have been used to examine the temperature dependence of various defect inductions. It is found that cracks in diamond film are generally derived at grain boundary. In general, diamond films prepared in high temperature substrate will result in high residual stress at the interface between the diamond film and the substrate.