Sidewall channel fabrication using membrane projection lithography and metal assisted chemical etching

Channels that run parallel and beneath the surface of an Si substrate are fabricated by first forming submicrometer sized disks of Au onto etched sidewall features in Si. The disks are formed by fabricating a patterned membrane mask of electron beam resist and evaporating Au at a 45° angle with respect to the substrate surface. Metal assisted chemical etching is then applied to remove the Si beneath the Au disks to form channels that lie perpendicular to these disk surfaces. Channels on the order of 300 nm in diameter have been fabricated by the combination of these techniques.