A study on the properties of microcrystalline and nanocrystalline diamond films synthesized by using a microwave PECVD method

In this study, diamond films were synthesized by using a microwave plasma-enhanced chemical vapor deposition (PECVD). H₂ and CH₄ gases were used on a Si wafer after pretreatment with a DC bias instead of the conventional scratch method. The synthesis of microcrystalline diamond films (MDC) was carried out in two steps. In the first step, diamond nuclei were created using a DC bias. In the second step, the DC bias was discontinued while an experiment for growing the nuclei created in the first step was performed. The synthesis of nanocrystalline diamond (NCD) films was carried out in a one-step process. The thickness and the surface of the synthesized film were measured using field-emission scanning electron microscopy. The diamond film's structure was analyzed using Raman and X-ray diffraction. Furthermore, the change in the refractive index of the film was measured with an ellipsometer.