Porous silicon (PSi) was fabricated based on anodic electrochemical etching, and the relationship between preparation conditions, nanostructure and PSi surface crack behavior were systematically studied. The effects of silicon wafer resistivity (doping concentration), etching time, and etching current density on nanostructure of PSi were investigated. Results indicated that lower resistivity was beneficial to etching process and led to higher porosity with uniform nano‐channels, and surface crack was more intense during drying process. Thickness and porosity of the porous layer are both initially increased and then decreased with increasing etching time. Direction of capillary stress depended on pore geometry, which further affected crack shape (shrinkage or crimp) of surface layer of PSi. Cracking extent was controlled by porosity, that the surface cracking layer began to peel off when the porosity exceeded 70%. Finally, a geometry and porosity‐controlled model was proposed to describe the cracking behaviors of PSi surface layer.

中文翻译：

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基于阳极电化学刻蚀的多孔硅制备及表面开裂行为研究Research

基于阳极电化学刻蚀工艺制备了多孔硅（PSi），系统地研究了制备条件，纳米结构与PSi表面裂纹行为之间的关系。研究了硅晶片电阻率（掺杂浓度），刻蚀时间和刻蚀电流密度对PSi纳米结构的影响。结果表明，较低的电阻率有利于蚀刻工艺，并导致具有均匀纳米通道的较高孔隙率，并且在干燥过程中表面裂纹更强烈。随着蚀刻时间的增加，多孔层的厚度和孔隙率都首先增加，然后减小。毛细应力的方向取决于孔的几何形状，孔的几何形状进一步影响了PSi表面层的裂纹形状（收缩或卷曲）。裂纹程度受孔隙度控制，当孔隙率超过70％时，表面裂纹层开始剥落。最后，提出了一种由几何和孔隙率控制的模型来描述PSi表面层的开裂行为。