Universal three-dimensional nanofabrication for hard materials

Three-dimensional (3D) nanofabrication technologies are entering new phases in advanced application fields, such as nanorobotics, metamaterials, and nanomechanical systems. In particular, the ability to arbitrarily create 3D nanostructures in hard materials like semiconductors and metals with nanometer-scale resolution will accelerate innovation in these fields, although a versatile technology applicable to various materials has not yet been established. The authors have devised a flexible 3D nanofabrication technique that is applicable to any material in principle. It uses 3D electron beam (EB) writing of arbitrary patterns followed by 3D ion etching, where the EB and ions fly in directions vertical and parallel to the substrate surface. Characteristics of the etching angle were investigated, and large angled etching of 88° was achieved. 3D nanostructures fabricated in single-crystal Si demonstrate that this technique has high resolution, high fabrication speed, and a large degree of freedom in the 3D shapes and dimensions that can be realized.