Development of high-efficiency wet polishing method for diamond substrate utilizing ultraviolet light / ozone gas

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K03876
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18020:Manufacturing and production engineering-related
• Research Institution: Kumamoto University
• Principal Investigator: Kubota Akihisa 熊本大学, 大学院先端科学研究部(工), 准教授 (80404325)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: ダイヤモンド / 精密研磨 / オゾン / 紫外光 / マイクロバブル

Outline of Final Research Achievements

In our previous study, we proposed a novel polishing technique for single-crystal diamond substrate using an iron plate in hydrogen peroxide (H2O2) solution. This technique used catalytically generated hydroxyl radicals (OH radicals), which were generated by the decomposition of H2O2 on the iron’s surface. Although an atomically smooth diamond surface could be obtained, the material removal rate (MRR) was extremely low.
In this study, to enhance the MRR of diamond substrate in wet processing, we developed a newly polishing technique with irradiating vacuum ultraviolet light and with supplying ozone microbubbles (O3-MBs) in H2O2 solution. We examined the polishing characteristics of the diamond substrates in this proposed polishing technique. The results indicate that the MRR was markedly improved about 2.7 times higher in our proposed technique. The surface roughness of the resultant diamond substrate was an atomically smooth with Ra =0.15 nm or less.

Free Research Field

精密加工

Academic Significance and Societal Importance of the Research Achievements

溶液環境下での加工によって，ダイヤモンド表面を原子スケールで平滑化できることを明らかにしたものであり，ダイヤモンド製パワー半導体デバイスやダイヤモンド製ヒートスプレッダの基板表面の作製方法の一手法として期待できる．