Microfabrication using one-step LPCVD porous polysilicon films

A simple, one-step LPCVD process was recently reported to allow the repeatable fabrication of polycrystalline silicon (polysilicon) thin films containing through-pores measuring 10-50 nm in diameter, as-deposited, with no additional processing steps required. This paper describes methods for using this one-step porous polysilicon material to quickly and easily fabricate structures of interest to MEMS designers. Among the structures presented are hermetically sealed diaphragms, hollow tube and shell structures, substrate-aligned membranes over one square centimeter in area ("supermembranes"), and permeable fluidic microchannels on silicon and quartz substrates.