Wen Qiuling, Wei Xinyu, Jiang Feng, Lu Jing, Xu Xipeng
Institute of Manufacturing Engineering, Huaqiao University, Xiamen 361021, China.
Fujian Engineering Research Center of Intelligent Manufacturing for Brittle Materials, Huaqiao University, Xiamen 361021, China.
Materials (Basel). 2020 Jun 26;13(12):2871. doi: 10.3390/ma13122871.
Sapphire substrates with different crystal orientations are widely used in optoelectronic applications. In this work, focused ion beam (FIB) milling of single-crystal sapphire with A-, C-, and M-orientations was performed. The material removal rate (MRR) and surface roughness (Sa) of sapphire with the three crystal orientations after FIB etching were derived. The experimental results show that: The MRR of A-plane sapphire is slightly higher than that of C-plane and M-plane sapphires; the Sa of A-plane sapphire after FIB treatment is the smallest among the three different crystal orientations. These results imply that A-plane sapphire allows easier material removal during FIB milling compared with C-plane and M-plane sapphires. Moreover, the surface quality of A-plane sapphire after FIB milling is better than that of C-plane and M-plane sapphires. The theoretical calculation results show that the removal energy of aluminum ions and oxygen ions per square nanometer on the outermost surface of A-plane sapphire is the smallest. This also implies that material is more easily removed from the surface of A-plane sapphire than the surface of C-plane and M-plane sapphires by FIB milling. In addition, it is also found that higher MRR leads to lower Sa and better surface quality of sapphire for FIB etching.
具有不同晶体取向的蓝宝石衬底在光电子应用中被广泛使用。在这项工作中，对具有A取向、C取向和M取向的单晶蓝宝石进行了聚焦离子束（FIB）铣削。得出了FIB蚀刻后三种晶体取向蓝宝石的材料去除率（MRR）和表面粗糙度（Sa）。实验结果表明：A面蓝宝石的MRR略高于C面和M面蓝宝石；FIB处理后A面蓝宝石的Sa在三种不同晶体取向中最小。这些结果意味着，与C面和M面蓝宝石相比，A面蓝宝石在FIB铣削过程中更容易去除材料。此外，FIB铣削后A面蓝宝石的表面质量优于C面和M面蓝宝石。理论计算结果表明，A面蓝宝石最外表面每平方纳米铝离子和氧离子的去除能量最小。这也意味着通过FIB铣削从A面蓝宝石表面比从C面和M面蓝宝石表面更容易去除材料。此外，还发现较高的MRR会导致FIB蚀刻的蓝宝石具有较低的Sa和更好的表面质量。
