Method of fabricating lateral nanopores, directed pore growth and pore interconnects and filter devices using the same

Abstract

Lateral pores in a thin metal film as well as fabricating branching and expanding ore arrays can be fabricated by a method of growing long pores laterally underneath a ask by use of stress compliant masks or varying the anodization voltage. Applications range from use with scanning electron microscope (SEM-compatible single molecule probe stations), to nanowire fixtures and to the use with a “pixelating, nonscanning” near field optical microscope (NOM). Pores are defined by conventional anodization vertically into the underlying membrane of preporous material through any overlying masking layers. The general solution is to utilize mechanically stable masks that withstand the stress during anodization and counteract the pore formation stress to lead to good pore ordering and directed growth. Multilayer masks are well suited for this. With a composition of materials having different elastic properties, tensile stress can be matched to counteract compressive stress caused by porous material growth. The boundary stress problem between preporous and porous material is solved by using a planarizing mask material that provides locally increased masking layer thickness at the critical boundary between nonporous and porous material in the film.