Formation of High Purity Glass Films for Planer Waveguide by Interfacial Polymerization

用界面聚合法研究了平面波纹硅酸盐玻璃厚膜的形成，重点研究了降低凝胶膜烧结温度的条件。第一年研究了不同催化剂存在下硅酸乙酯前驱体凝胶膜的形成机理。组成薄膜的二氧化硅颗粒在界面上方的有机相中成核和生长，表明具有高溶解性的碱催化剂如三乙胺是有效的。然而，组成薄膜的颗粒太大，不能应用于在硅衬底上形成的薄膜，这表明有必要添加硼或锗来降低烧结温度。第二年研究了由四甲氧基硅烷和三甲基硼酸酯制备的前驱体凝胶膜的形成，以降低膜的烧结温度。以三乙胺为催化剂形成的凝胶具有良好的组成和厚度重现性。在1100ﾟ℃下，SiO_2-B_2O_3系薄膜被烧结成无孔玻璃薄膜，该温度低到足以应用于硅衬底上的平面波导。

The formation of thick silicate glass film for a planer wavegide has been studied by an interfacial polymerization focusing on the conditions to reduce the sintering temperature of a gel film. The mechanism of gel film formation from ethylsilicate precursor at the existence of various kinds of catalyst was investigated in the first year. The nucleation and growth of silica particles comprising the film proceeded in the organic phase immediately above the interface, showing that a base catalyst having a high solubility such as triethylamine is effective. The size of particles comprising the film was, however, too large to be applied to a film formed on a silicon substrate, suggesting that the addition of boron or germanium was necessary to reduce the sintering temperature. The gel film formation from a precursor prepared from tetramthoxysilane and trimethylborate was investigated in the second year in order to reduce the sintering temperature of the film. A good reproducibility of composition and thickness was obtained for the gel formed using triethylamine as a catalyst. The film of SiO_2-B_2O_3 system was sintered to a pore free glass film at 1100ﾟC,which is low enough for the application to the planer waveguide on silicon substrate.