SPATIALLY CONTROLLED MEMBRANE DEPOSITIONS FOR SILICON-BASED SENSORS

The membrane deposition technology on silicon-based transducers consti tutes the most delicate part of the miniaturized (bio)chemical sensor fabrication. Membrane adhesion to the transducer, reproducibility of t he deposition process and its spatial control are the three most impor tant parameters which determine the sensor performance and lifetime. T he fabrication of two sensors is described: 1) a combined pO2, pCO2, p H sensor for which a polyacrylamide gel and a polysiloxane gas-permeab le membrane were deposited and patterned at the on-wafer level and 2) a glucose amperometric enzyme electrode where the glucose oxidase was immobilized electrochemically either in a polypyrrole matrix or co-dep osited with bovine serum albumin by electrochemically aided adsorption . The optimization of the deposition procedures allowed reproducible d evices with reasonable lifetimes to be obtained.