触媒表面基準エッチングによるＳｉＣ加工のメカニズム解明

通过对第一年进行的水CARE反应机理的阐明，CARE反应的中间态是通过OH的O(吸附在目标硅上)与催化金属之间的化学键来稳定的。由于这种稳定，活化能降低，并且CARE反应有可能在室温下发生。今年，通过使用不同的催化剂调节O与O的化学键，我们观察到清除率明显依赖于这个结合能。当这个结合能太低时，反应不会被促进。因此，去除率很低。当结合能过高时，催化剂的活性会因中毒而降低。因此，去除速度也很慢。为了优化催化剂的性能，我们提出使用合金催化剂，并取得了显著的效果。此外，实验结果还表明，水保护对亚硝酸盐半导体GaN也是有效的。同时，通过第一性原理计算阐明了GaN的刻蚀机理。结果表明，GaN的水合反应可以通过类似于碳化硅刻蚀的水解反应进行。目前正在编写本成果，以供出版。

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.