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

通过阐明第一年进行的水-CARE反应的机理，CARE反应的中间态通过OH中的O（吸附在目标Si上）与催化金属之间的化学键稳定。由于这种稳定性，活化能降低，CARE反应可能在室温下发生。今年，通过使用不同的催化剂调整这种与O的化学键，我们观察到了去除率对这种结合能的明显依赖性。当该结合能太低时，不能促进反应。因此，去除率低。当该结合能过高时，催化活性由于中毒而降低。因此，去除速度也很慢。为了优化催化剂的性能，我们提出了使用合金催化剂，并取得了显著的效果。此外，实验结果表明，Water-CARE对GaN（一种亚硝酸盐半导体）也有效。同时，我们通过第一性原理计算阐明了GaN刻蚀的机理。结果，揭示了GaN的Water-CARE可以通过与SiC蚀刻类似的水解反应进行。目前正在准备公布这些结果。

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.