Development of Macroporous Silicon for Bio-Chemical Sensing Applications

Macroporous silicon bio-chemical sensing devices have been developed, fabricated and tested. The porous silicon walls were lined with oxide and aluminum electrodes were placed on either side of the porous silicon membrane. These electrodes were used to measure capacitive changes resulting from vapor/fluidic interactions with the oxide-coated porous silicon membrane. For thick flow-through membrane formation, the maximum etch time investigated during the porous silicon-forming anodization process, using an electrolyte consisting of hydrofluoric acid and dimethylformamide was an 8 hour period with an electrolyte refresh halfway through the process. The pore dimensions measured after this process were approximately 67 μm at the center and 102 μm at the edge, with a pore width of 1.6 μm to 1.65 μm, respectively. The propagation was highly anisotropic with vertical pore sidewall profiles. Flow-through membrane structure devices were realized and electrical data was collected