为深入了解熔石英元件化学刻蚀过程,研究了HF刻蚀反应机理、HF刻蚀工艺参数以及刻蚀对表面质量的影响规律。通过控制变量法,获得刻蚀速率随HF浓度、刻蚀温度以及NH4F浓度的变化规律。对刻蚀不同深度后的元件表面粗糙度、形貌、杂质含量以及激光损伤阈值进行了检测,实验结果表明:刻蚀速率受多种因素共同影响,其中HF浓度的促进作用最为显著;刻蚀后的熔石英表面形貌复杂,有横向、纵向、拖尾等形式的划痕,以及坑点、杂质等缺陷,其中横向划痕和纵向划痕占据了缺陷部分的主体,主要杂质铈元素随刻蚀时间的增长不断减少;激光损伤阈值测量实验表明,通过HF刻蚀将元件损伤阈值提高了59.6%。
In order to understand the chemical etching process of fused silica, the reaction mechanism, processing parameters and the influence of HF etching on the etched surface quality are investigated. The effects of HF concentration, temperature and NH4 F concentration on etching rate are obtained by performing the single factor experiment. The surface roughness, morphology, impurity content and damage threshold of the post-etched components are measured, and the experimental results indicate that the etching rate is influenced by a variety of factors, in which the effect of HF concentration is the greatest. The mor phology of the HF-etched fused silica surface is complex, containing scratches, pits, impurities and other defects. And the main forms of defects are transverse and longitudinal scratches. The content of the main impurity defect decreases with the increase of etching time. The laser damage test shows that the damage threshold of fused silica is increased by 59.6% through the HF etching process.