Chemical Mechanical Polishing of MgO Substrate and Its Effect on Fabrication of Atomic Step-Terrace Structures on MgO Surface by Subsequent High-Temperature Annealing
| Autor: | Hideo Aida, Takumi Ojima, Ryuji Oshima, Takahiro Ihara, Hidetoshi Takeda, Yutaka Kimura, Atsuhito Sawabe |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | ECS Journal of Solid State Science and Technology. 11:114005 |
| ISSN: | 2162-8777 2162-8769 |
| DOI: | 10.1149/2162-8777/aca3d1 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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