硅氢键对波导表面光滑化影响的理论仿真

低损耗高Q值硅基纳米光波导谐振腔，是高灵敏探测器、生物传感器、光通讯器件等发展的关键。而波导表面粗糙度会造成较大的光传输损耗，是制约硅基纳米光波导谐振腔Q值提高的一个重要因素。降低硅基纳米光波导表面粗糙度已成为光波导器件发展的一个关键问题，氢退火工艺是当前改善波导表面粗糙度的一种关键技术。基于表面硅氢键流密度理论，利用Materials Studio软件模拟氢退火光滑化处理过程中硅与氢之间的反应，搜索反应过渡态，探究硅氢键、温度等因素对反应的影响。结果表明:在高温氢退火氛围下，波导表面硅原子与氢原子之间能够形成硅氢键，且温度越高，在硅氢键作用下表面硅原子迁移速率越快，表面由高能态向低能态过渡，表面光滑化效果越明显。

Theoretical simulation of the effect of silicon hydrogen bond on waveguide surface smoothing

Si nano-optical waveguide resonant cavity with low loss and high Q value is the key for high sensitivity detectors, biosensors, optical communication devices, and so on. However, the surface roughness of optical waveguide will cause high transmission loss which becomes a serious constrain to the high Q value of Si nano-optical waveguide resonant cavity. Therefore, it has become a key issue to reduce the surface roughness of silicon-based nanometer optical waveguide for the development of photonic devices. Nowadays hydrogen annealing technology is an important method to reduce the surface roughness of waveguide. According to the theory of surface Si-H bond current density, the simulation study was done by Materials Studio software. The reaction between silicon atoms and hydrogen atoms in the smoothing process of hydrogen annealing was simulated. The reaction transition state was searched. The influence of silicon hydrogen bond and temperature on the reaction process was also studied. The results indicate that chemical bond can be formed between silicon atom and hydrogen atom under high temperature with H2 atmosphere. Higher temperature is benefit to accelerate the moving rate of surface silicon atoms which makes the surface transition from upper state to lower state, and realize its smoothing.