The Study Of Diamond Films And Its Composite Films Deposited By Bias Voltage HFCVD

The technology of preparing diamond film is a crucial role in gaining high diamond nucleation density and high-quality diamond film, and the improvement of adhesion between the diamond film and substrate is of vital industrial significance, such as in the case of severe wear surface coatings, optic devices, etc. The major contributions of this dissertation include the following aspects:1. An improving HFCVD technology to prepare the diamond filmThe influence of substrate bias, methane concentration, carbon source on nucleation, morphology and crystallography of grown diamond films deposited by homemade HFCVD apparatus were investigated. The samples were characterized by atomic force microscopy (AFM), filed emission scanning electron microscopy (FE-SEM) and X-ray diffraction measurements (XRD). By analyzing the results, conclusions were drown as followings:(1) The positive bias plays an important role on diamond nucleation. The diamond nucleation density could be increased when the substrate was applied proper positive bias voltage. The phenomena were explained by electron sheath the theory. And the diamond film was prepared by a new direct current plasma-hot filament chemical vapor deposition technology.(2) In a methane concentration range of 1%~4%, with the increase of methane concentration the diamond nucleation density and deposition rate increased.(3) The deposition rate and quality of diamond film deposited using ethanol as carbon source was higher and better compared with methane.(4) The model of diamond growth belongs to island growth model through observing a series of diamond film growth process.