Study On The Optical Characteristics Of Interface Layer Of Deposition Diamond-like Carbon Films

When there are many high-energy particles participation in DLC films during the DLC films deposition process, the interface state of multilayer optical thin film was changed. Studying the effects of preparation technology and technological parameters on interface of films are meaningful for the analysis of the optical loss mechanism of hydrogen-free DLC films in near-infrared.The influences of technological parameters on the interface layer thickness, refractive index, extinction coefficient were studied by the method of testing and analysis of interface layer parameters of diamond-like carbon in this paper. The influences of interface layer parameters on transmittance were explored.The results of this study are given as follows:1) When the DLC films were prepared by UBMS, the target current played a key role on the thickness of the interface layer. The thickness of the interface layer decreased from 56.7nm to 44.2nm with the target-substrate increase from 102mm to 162mm. When the target current changed from 0.5A to 0.9A, the excitation current increased from 40A to 60A, the vacuum decreased from 0.5Pa to 0.7Pa, the excitation current influenced the refractive index, the extinction coefficient of the interface layer.2) When the DLC films were deposited by the combination of UBMS and PVAD, the properties of the interface layer are given as follow:Keeping the optical thickness of DLC unchanged, with the thickness of DLC by PVAD deposition increase from 74.8nm to 117.0nm, the thickness of the interface layer increase from 50.0nm to 62.0nm, the refraction increase from 2.426 to 2.511, and the extinction coefficient decrease from 0.0155 to 0.0134. The transmittance of DLC films increase with the increment of the thick of the PVAD films. The transmittance of DLC film deposited on Si substrate can reach its maximum of 68.77% in the wavelength range of 2.0-5.Oum.