Shi Dachuang, Chen Yun, Li Zijian, Dong Shankun, Li Liyi, Hou Maoxiang, Liu Huilong, Zhao Shenghe, Chen Xin, Wong Ching-Ping, Zhao Ni
State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment, School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
School of Electronic Science and Engineering, Southeast University, Nanjing, Jiangsu, 211189, China.
Small Methods. 2022 Aug;6(8):e2200329. doi: 10.1002/smtd.202200329. Epub 2022 May 26.
Wet etching of silicon carbide typically exhibits poor etching efficiency and low aspect ratio. In this study, an etching structure that exploits anisotropic charge carrier flow to enable high-throughput, external-bias-free wet etching of high-aspect-ratio SiC micro/nano-structures is demonstrated. Specifically, by applying a catalytic metal coating at the bottom surface of a SiC wafer while introducing patterned ultraviolet light illumination from its top surface, spatial charge separation across the wafer is achieved, i.e., photogenerated electrons are channeled to the bottom to participate in the reduction reaction of an oxidant in the etchant solution, while holes flow to the top to trigger oxidation of SiC and subsequent etching. Such design largely suppresses recombination-induced charge losses, and when used in combination with a top metal catalyst mask, the structure yields a remarkable vertical etching rate of 0.737 µm min and an aspect ratio of 3.2, setting new records for wet-etching methods for SiC.
碳化硅的湿法蚀刻通常表现出蚀刻效率低和纵横比小的问题。在本研究中，展示了一种利用各向异性电荷载流子流动实现高通量、无外部偏压的高纵横比碳化硅微纳结构湿法蚀刻的蚀刻结构。具体而言，通过在碳化硅晶片底面施加催化金属涂层，同时从其顶面引入图案化紫外光照射，实现了晶片内的空间电荷分离，即光生电子被引导至底面参与蚀刻剂溶液中氧化剂的还原反应，而空穴流向顶面引发碳化硅的氧化及随后的蚀刻。这种设计极大地抑制了复合诱导的电荷损失，并且当与顶部金属催化剂掩膜结合使用时，该结构产生了显著的垂直蚀刻速率0.737 µm/min和3.2的纵横比，为碳化硅的湿法蚀刻方法创造了新纪录。
