Chemical Mechanical Polishing of MgO Substrate and Its Effect on Fabrication of Atomic Step-Terrace Structures on MgO Surface by Subsequent High-Temperature Annealing
Chemical Mechanical Polishing of MgO Substrate and Its Effect on Fabrication of Atomic Step-Terrace Structures on MgO Surface by Subsequent High-Temperature Annealing
复制标题
MgO 基板的化学机械抛光及其对后续高温退火在 MgO 表面形成原子阶梯结构的影响
DOI：
10.1149/2162-8777/aca3d1
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发表时间：
2022
影响因子：
2.2
通讯作者：
Sawabe Atsuhito
中科院分区：
文献类型：
--
作者：
Aida Hideo;Ojima Takumi;Oshima Ryuji;Ihara Takahiro;Takeda Hidetoshi;Kimura Yutaka;Sawabe Atsuhito
单晶MgO被用作沉积各种功能薄膜的衬底。本研究的重点是通过研磨，精密机械抛光，化学机械抛光（CMP）和高温退火的方法，在MgO衬底上制造原子台阶平台结构的完整序列的发展。研究了无损伤表面预处理对后续高温退火的影响。通过使用胶体二氧化硅浆料的CMP工艺获得了平均表面粗糙度为0.05 nm的原子级光滑且无损伤的MgO衬底表面。在1000 ℃、20 h的高温退火处理后，衬底上形成了原子台阶结构。得到的台阶高度为0.20 nm，相当于MgO结晶的晶胞的一半（0.21 nm）。相比之下，当机械损伤的MgO基板进行退火过程中，钙偏析观察退火表面上，没有形成一个原子的台阶-平台结构。CMP被认为是必要的高温退火之前，以获得原子台阶的平台结构，并避免在MgO大块晶体中的杂质的扩散。
Single-crystalline MgO is used as a substrate for the deposition of various functional thin films. The present study focused on the development of a complete sequence of fabricating atomic step-terrace structures on the MgO substrate via a method that includes grinding, precise mechanical polishing, chemical mechanical polishing (CMP), and high-temperature annealing. The effect of a damage-free surface pretreatment on the subsequent high-temperature annealing was investigated. An atomically smooth and damage-free MgO substrate surface with an average surface roughness of 0.05 nm was obtained via a CMP process using a colloidal silica slurry. Atomic step-terrace structures were formed on the substrate after the high-temperature annealing process at 1000 C for 20 h under atmospheric air. The obtained step height was 0.20 nm, which corresponds to one-half the unit cell of an MgO crystal (0.21 nm). By contrast, when a mechanically damaged MgO substrate was subjected to the annealing process, Ca segregation was observed on the annealed surface, without the formation of an atomic step-terrace structure. CMP was found to be necessary prior to high-temperature annealing to attain atomic step-terrace structures and to avoid the out-diffusion of impurities in the MgO bulk crystals.