Site-controlled preparation of metallic microstructures via mechanical scratch-induced selective electrodeposition

Controlled preparation of metallic microstructures attracts wide interest in sensor and electronic fields. However, limited by fabrication technology, it faces challenges in achieving template-free and orientational formation of metallic microstructures. Herein, a site-controlled strategy via scratch-induced selective electrodeposition was proposed to prepare high-quality metallic structures on silicon (Si) surface with the assistance of scanning probe lithography (SPL). The effects of scratching and depositing conditions were systematically investigated for optimizing the preparation process. Selective electrodeposition mechanisms were addressed through topographic and conductive detections. It was found that single-cycle scratch created under higher loads was beneficial for preparing compact and continuous Cu structures. Further analysis indicated that higher normal loads in scratching can facilitate obtaining more conductive sites, promoting orientated migration of metal ions during the reaction, while the increase of reciprocating cycles can cause more amorphous layers and hinder electron transport. Moreover, post-annealing treatment can lead to the growth of Cu grain sizes, which contributes to the crystallinity. Notably, the proposed method is demonstrated with the preparation of Cu coils, which is sensitive to alternating magnetic field. These findings shed new light on the site-controlled preparation of high-quality metallic microstructures and the applications.