In order to fabricate truly complex three-dimensional (3D) silicon nanostructures fabrication methods which expand beyond the concept of creation of straight 3D structures by direct extension of two dimensional (2D) patterns need to be developed. In recent years Metal assisted Chemical Etching (MaCE) of silicon, in which etching is confined to a small region surrounding metal catalyst templates, has emerged as a promising low cost alternative to commonly used 3D fabrication techniques. We report a new methodology for controllable folding of 2D metal catalyst films into 3D structures using MaCE process. The introduced method takes advantage of selective patterning of the catalyst layer into regions with mismatched characteristic dimensions, resulting in uneven etching rates along the notched boundary lines that produces hinged 2D templates for 3D folding. We explore the dynamics of the folding process of the hinged templates, demonstrating that the folding action combines rotational and translational motion of the catalyst template, which yields topologically-complex, hybrid 3D nanostructures with intimately-integrated metal and silicon features.
Citation: Nano Letters
Pub Type: Journals
Metal assisted Chemical Etching, 3D nanostructures, self assembly