Raman Spectroscopy Studies on DLC Films Synthesized by PECVD Method

摘要

Diamond like carbon (DLC) is a metastable form of amorphous carbon containing fraction of sp~2 and sp~3 bonds. Their mechanical properties depend on the sp~3 content as well as on the number and size of graphitic nanoclusters. It is noted that properties change significantly depending on the method of preparation of these films. These properties are also altered by the composition of the films. In view of this, the objective of present work was to deposit hydrogenated DLC films on p-type silicon substrate using inductively coupled plasma enhanced chemical vapor deposition (IC-PECVD) technique with varying bias voltage, bias frequency, gas deposition pressure and gas composition ratio. They play an important role in film deposition process and are responsible for change in mechanical properties of the film such as hardness and Young's modulus. Raman spectroscopy was used to study the structural arrangement of carbon atoms. Significant change in the mechanical properties of the film was observed which can be attributed to the change in sp~3 and sp~2 contents in the DLC film. It was observed that the process parameters considerably affect the hardness and Young's modulus of the DLC films. The films of desired mechanical properties can be deposited for various industrial and biomedical applications by maintaining suitable deposition conditions.