Fabrication of Lateral Porous Silicon Membranes for Planar Microfluidic Devices

Abstract

Abstract In this work, we present a novel fabrication process to create lateral porous silicon membranes. The advantage of this process is to enable the monolithic integration of porous silicon directly into planar microchannels, thus greatly simplifying the integration of membranes into fluidic devices and opening doors to the use of porous silicon into planar lab-on-a-chip devices for filtering purposes. The presented fabrication technique relies on the patterning of local electrodes within microchannels to carry out silicon anodization parallel to the surface of the silicon substrate. The feasibility of our approach is demonstrated by creating 10 μm long mesoporous membranes within 3 μm deep microchannels. Our experimental results are supported by current flow studies using finite element analysis.