Properties of diamond films with various thicknesses synthesized by using the microwave PECVD method

In this study, a diamond films were pretreated using the direct current (DC) bias method instead of the existing scratch method and were synthesized using the microwave plasma enhanced chemical vapor deposition method by applying H2 and CH4 gases to the Si wafers. The diamond films were synthesized in two steps. First, a DC-bias was applied for diamond nucleation. Second, the DC-bias was removed, and the nucleus that had been created in the first step grew. To examine the film thickness as a function of the synthesis time of the growth phase and to analyze its characteristics for various thicknesses, we performed experiments under conditions identical to those in the DC-bias nucleation stage. Synthesis times of 20, 40, 60, or 120 min were used to examine the characteristics of the diamond films with respect to the synthesized film’s thickness. Field emission scanning electron microscopy (FE-SEM) was used to identify the thickness, while Raman spectroscopy and X-ray diffraction (XRD) were used to analyze the diamond film structure. The change in the film’s refractive index was measured using an ellipsometer.