计算机模拟类金刚石薄膜的光学性能研究

Dielectric Properties of Diamond- like Carbon Films Obtained by Simulating Optical Spectrum

采用射频等离子体化学气相法在BK7玻璃样品上合成了类金刚石薄膜，基于介电模型对样品的光学透射谱进行计算机拟合，得到类全刚石薄膜的折射率和膜厚等性能指标。研究了甲烷浓度，射频功率密度和沉积压力等工艺参数对类金刚石薄膜的光学特性影响规律。试验表明折射率和生长速率均随甲烷浓度和功率密度增加而增加；气体压力对生长速率的影响最显著。

Diamond -like carbon （DLC） films were deposited on glass substrate at room temperature by radio frequency plasma enhanced chemical vapor deposition （ RFPECVD）. Optical properties of the deposited films were investigated using spectroscopy at wave number range of 200 -2500cm^-1. Some optical constants, such as reference index and extinction coefficient, film thickness, energy loss function, absorption coefficient, and dielectric functions can be obtained by simulating measured optical spectrum using a computer program based on dielectric function models of substrate and film materials. The influence of deposition parameters including methane concentration, power density, and chamber pressure, on the optical properties has been detailedly studied. Results indicated that the growth rate and reference index increased with increasing the methane and RF power density. The growth rate was very sensitive to deposition pressure.