| 研究実績の概要 |
By the elucidation of the mechanism of Water-CARE conducted in the first year, the intermediate state of CARE reaction is stabilized by chemical bonds between O of OH (adsorbed on a targeted Si) and a catalytic metal. Thanks to this stabilization, the activation energy is reduced and the CARE reaction is possible to occur at the room temperature. This year, by tuning this chemical bond with O using different catalysts, we observed a clear dependence of the removal rate on this binding energy. When this binding energy is too low, the reaction is not promoted. Therefore, the removal rate is low. When this binding energy is too high, the catalytic activity is reduced due to the poisoning. Thus, the removal rate is also slow. For the optimization of the catalyst performance, we proposed using an alloy catalyst and gained significant results. Additionally, experimental results showed that Water-CARE is also effective for GaN, a nitrite semiconductor. In parallel, we clarified the mechanism of the GaN etching by first-principles calculation. As a result, it was revealed that Water-CARE of GaN can be progressed by the hydrolysis reaction which is similar to that of the SiC etching. The present results are currently being prepared for publication.
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