RIE process for fabricating submicron, silicon electromechanical structures

Claim 1

A reactive ion etching process for fabricating a high aspect ratio, submicron, released, single crystal silicon electromechanical structure independently of crystal orientation, comprising: forming a patterned etch mask on a top surface of a single crystal silicon substrate, the etch mask defining a structure of arbitrary shape to be formed in said substrate, said shape being independent of crystal orientation in said substrate; transferring the pattern of said etch mask to said substrate and forming by reactive ion etching trenches defining the structure to be fabricated in the substrate, said etching step forming trenches having bottom walls and vertical side walls; forming an electrically insulating silicon dioxide layer on exposed surfaces of said silicon substrate, the exposed surfaces including said vertical side walls of said trenches; forming metal electrodes on selected portions of said vertical side walls; selectively removing said silicon dioxide insulating layer from said bottom walls of said trenches to expose said single crystal silicon substrate; and reactive ion etching the exposed bottom wall substrate to undercut and to mechanically release said defined structure from said substrate to thereby produce a high aspect ratio, released, single crystal silicon structure having vertical side walls, said released structure being relatively movable with respect to said substrate.