Woo Seouk-Hoon, Hwangbo Chang Kwon
Department of Physics, Inha University, Incheon 402-751, South Korea.
Appl Opt. 2006 Mar 1;45(7):1447-55. doi: 10.1364/ao.45.001447.
Effects of thermal annealing at 400 degrees C on the optical, structural, and chemical properties of TiO2 single-layer, MgF2 single-layer, and TiO2/MgF2 narrow-bandpass filters deposited by conventional electron-beam evaporation (CE) and plasma ion-assisted deposition (PIAD) were investigated. In the case of TiO2 films, the results show that the annealing of both CE and PIAD TiO2 films increases the refractive index slightly and the extinction coefficient and surface roughness greatly. Annealing decreases the thickness of CE TiO2 films drastically, whereas it does not vary that of PIAD TiO2 films. For PIAD MgF2 films, annealing increases the refractive index and decreases the extinction coefficient drastically. An x-ray photoelectron spectroscopy analysis suggests that an increase in the refractive index and a decrease in the extinction coefficient for PIAD MgF2 films after annealing may be related to the enhanced concentration of MgO in the annealed PIAD MgF2 films and the changes in the chemical bonding states of Mg 2p, F 1s, and O is. It is found that (TiO2/MgF2) multilayer filters, consisting of PIAD TiO2 and CE MgF2 films, are as deposited without microcracks and are also thermally stable after annealing.
研究了400℃热退火对通过常规电子束蒸发（CE）和等离子体离子辅助沉积（PIAD）制备的TiO2单层、MgF2单层以及TiO2/MgF2窄带通滤光片的光学、结构和化学性质的影响。对于TiO2薄膜，结果表明，CE和PIAD TiO2薄膜的退火均会使折射率略有增加，消光系数和表面粗糙度大幅增加。退火会使CE TiO2薄膜的厚度急剧减小，而PIAD TiO2薄膜的厚度则无变化。对于PIAD MgF2薄膜，退火会使折射率增加，消光系数急剧减小。X射线光电子能谱分析表明，退火后PIAD MgF2薄膜的折射率增加和消光系数减小可能与退火后的PIAD MgF2薄膜中MgO浓度的增加以及Mg 2p、F 1s和O 1s化学键合状态的变化有关。发现由PIAD TiO2和CE MgF2薄膜组成的（TiO2/MgF2）多层滤光片在沉积时无微裂纹，退火后也具有热稳定性。
