物理法和化学法制备的单层ZrO_2膜的激光损伤行为差异

Comparison of laser-induced damage of monolayer ZrO_2 films preparated by PVD and sol-gel methods

分别采用电子束热蒸发技术和溶胶-凝胶技术在K9基片上镀制了光学厚度相近的ZrO2单层薄膜,测试了两类薄膜的激光损伤阈值。分别采用透射式光热透镜技术、椭偏仪、原子力显微镜和光学显微镜研究了两类薄膜的热吸收、孔隙率、微观表面形貌、激光辐照前薄膜的杂质和缺陷状况以及激光辐照后薄膜的损伤形貌。实验结果表明:两类薄膜的不同损伤形貌与薄膜的热吸收与微观结构有关,物理法制备的ZrO2膜结构致密紧凑,膜层的杂质和缺陷多;化学法制备的ZrO2膜结构疏松多孔,膜层纯净杂质少,激光损伤阈值达26.9 J/cm2;因物理法制备的ZrO2膜拥有更大的热吸收(115.10×10-6)和更小的孔隙率(0.20),其激光损伤阈值较小(18.8 J/cm2),损伤主要为溅射和应力破坏,而化学法制备的ZrO2膜的损伤主要为剥层。理论上对实验结果进行了解释。

The monolayer zirconia PVD and sol-gel films deposited on K9 glass substrates were prepared with electron beam evaporation method and spin method respectively. Both the films have similar optical thickness. The laser-induced damage threshold （LIDT） of the two kinds of films was measured. The thermal absorption, porous ratio and the surface morphologies of the films were investigated by Stanford photo-thermal solutions, ellipsometer and atomic force microscopy, respectively. Optical microscopy was used to characterize the defects and impurities of the films before laser irradiation and damage morphology after laser irradiation. The experimental results showed that the different damage morphologies of the two kinds of films were relative to their thermal absorption and microstructure. The zirconia PVD film had a dense and compact structure and much defects or impurities. The zirconia sol-gel film had a porous structure and less defects or impurities, and its LIDT was 26.9J/cm^2. Therefore the zirconia PVD film had larger absorption （115.10×10^-6） and smaller porous ratio（0.20）, and it had smaller LIDT （18. 8 J/cm^2）. For the zirconia PVD film, the damage morphology was a combination of sputter and stress rupture. While for the zirconia sol-gel film, the damage morphology was mostly delamination. Explanation was presented theoretically at last.