在硅片上沉积厚二氧化硅的火焰水解法研究

用火焰水解和高温烧结的方法在单晶硅基片上制备了厚SiO2和B2O2-P2O2-SiO2光波导包层材料。并用扫描电镜(SEM)和X射线粉末衍射(XRD)方法对其微观形貌和物相结构进行了观察和检测。重点对硅基片上沉积厚SiO2时的龟裂和析晶问题进行了深入研究。从扫描电镜照片可以看出．火焰水解法形成的SiO2粉末呈多孔的蜂窝状结构。这种粉末具有很高的比表面积，因而很容易烧结成玻璃。X射线衍射图谱表明．这种粉末是完全非晶态的。经过烧结以后，从扫描电镜照片可以明显看出硅基片上的SiO2薄膜出现龟裂。同时，X射线衍射测试结果表明有少量SiO2析晶。而通过在SiO2中掺入B2O3、P2O5，上述龟裂和析晶完全消失。用这种工艺制备的SiO2波导包层材料厚度达到20μm以上，表面光滑、没有龟裂，而且是完全玻璃态的，可以用于制备性能优良的各种硅基二氧化硅波导器件。

Research on the Deposition of Thick Silica on Silicon Substrate by Flame Hydrolysis Deposition

Thick SiO 2 and B 2O 3-P 2O 5-SiO 2 cladding materials for waveguide are fabricated on single crystal silicon substrate by flame hydrolysis deposition and high-temperature consolidation. The micro morphologies and phase structures of the samples are observed by scanning electron microscope (SEM) and X-ray diffraction (XRD). The main research focuses on the cracking and crystallizing of the thick silica film deposited on silicon substrate. It can be seen from the SEM photo that the silica particles are porous and like a honeycomb. These particles have very high ratio surface area, which make it consolidated to form glass easily. The XRD spectrum indicates that these particles are completely non-crystal. But after consolidation, it can be seen obviously from the SEM photo that cracks appears on the silica film on the silicon substrate. And the XRD result shows a little of silica crystallized. However, the above-mentioned cracks and crystallization disappeared thoroughly by doping with small amount of B 2O 3 and P 2O 5 into SiO 2. The silica waveguide cladding material fabricated by this procedure has a thickness above 20 micrometers. It has smooth and crack free surface and non-crystal phase structure. This B 2O 3-P 2O 5-SiO 2 cladding material is very fit for fabricating all kinds of silica-on-silicon waveguide devices.