A new technique for fabricating three-dimensional micro- and nanostructures of various shapes

In this paper we show that complex three-dimensional micro- and nanostructure shells can be formed by directional rolling up of thin strained Si/SiGe heterostructures. By lifting strain-designed Si/SiGe films using a sacrificial layer from the substrate and by a proper patterning prior to the etching almost arbitrary-shaped three-dimensional structures can be fabricated. A technique for controlling the shape and location of the structures is proposed and realized. In addition we show that it is possible to obtain cylindrical objects with the axes perpendicular to the substrate surface, and the objects themselves can be located at prescribed places on the substrate.