熔石英表面杂质元素在酸蚀过程中的变化

Change of surface impurity elements in the process of acid etching on fused silica

为了探寻熔石英表面痕量杂质元素种类以及随HF酸蚀刻过程中的变化情况,用质量分数为1%HF酸溶液对熔石英进行长达24,48,72,96h的静态蚀刻实验。结合飞行时间二次离子质谱(TOF-SIMS)和X射线光电子能谱(XPS)测试分析结果发现,熔石英试片表面的痕量杂质元素主要含有B,F,K,Ca,Na,Al,Zn和Cr元素,其中绝大部分都存在于贝氏层中,在亚表面缺陷层检测到有K,Ca元素。所含有的K,Na杂质元素会与氟硅酸反应生成氟硅酸盐化合物。分析表明,在HF酸蚀刻的过程中一部分杂质元素将被消除,一部分杂质元素和生成氟硅酸盐化合物会随着蚀刻液逐渐从熔石英表面向表面纵深方向扩散并被试片吸附沉积,且随着深度的加深各元素的相对含量逐渐减少。

In order to explore the elements of trace impurities in fused silica and the change of them during HF acid etching process,the static etching experiments of 24 h,48h,72 h,96hwere performed by the mass fraction of 1% HF acid solution.The results of TOF-SIMS and XPS show that,the fused silica surface mainly contains eight trace impurity elements,including B,F,K,Ca,Na,Al,Zn,Ca,and Cr;most of these elements are in the Beiby layer,and K and Ca impurity elements are detected in the subsurface defect layer;fluosilicate salts of K,Na are generated.By analysis,during the process of HF acid etching,apart of the impurity elements will be removed,and a portion of the impurity elements and the fluosilicate salts will diffuse gradually from the surface of the fused silica to the depth with the etching liquid while some will be absorbed by fused silica surface and deposit,and the contents of them reduce gradually with the increase of the depth.