脉冲激光沉积法制备红外光学SiC薄膜特性研究

采用脉冲激光沉积法在锗基底制备无氢SiC薄膜，研究了激光能量对SiC薄膜显微结构、成分和红外光学性能的影响规律。利用傅里叶红外光谱仪测量了锗基底SiC薄膜样品的红外透射光谱，其在785 cm-1附近有一个强烈Si-C键特征吸收峰，并在红外波数4 000~1 300 cm-1之间具有良好的透过性。通过对透射光谱拟合计算可知:在红外波段2.5~7.7 m之间，SiC薄膜的折射率和消光系数均随着激光能量的增加而增大，折射率大约从2.15上升到2.33，激光能量从400 mJ增加到600 mJ，且当激光能量为400、500 mJ时，消光系数均在10-3量级以内，光学吸收很小。研究表明，SiC薄膜在红外2.5~7.7 m波段是一种优异的光学薄膜材料。

Research on infrared optical properties of SiC films by pulsed laser deposition

Non-hydrogen silicon carbide (SiC) films were deposited on germanium substrate by pulsed laser deposition. The effects of laser energy on the microstructure, composition and infrared optical properties of SiC films were investigated. The infrared transmittance spectrums of SiC films were measured by Fourier transform infrared spectroscopy (FTIR). The spectroscopy analysis showed that the characteristic absorption peak of Si-C bonding was found at 785 cm-1, and the SiC films had good transmittance in the range of 4 000-1 300 cm-1. The optical constants of the SiC films were derived by fitting transmittance spectrum curves. It was found that the refractive index and the extinction coefficient of SiC films increased monotonicly with laser energies increasing in the range of 2.5-7.7 m. The refractive index changed from 2.15 to 2.33 as laser energies increased from 400 mJ to 600 mJ. The extinction coefficient was of the order of 10-3 when laser energies were of 400 mJ and 500 mJ. This study indicates that the SiC film is an excellent optical film material between 2.5 m to 7.7 m.