Simulation and fabrication of SiO₂-based piezoresistive microbridges for chem/biosensors

This paper uses finite element design for optimization of piezoresistive silicon covered SiO 2 microbridges. Resistance changes of the microbridge due to the surface stress changes were systematically investigated by varying Si piezoresistor geometries and the boron doping concentrations in silicon. Our simulation results show that the resistance change of the microbridge is directly related to the arcuation of the microbridges and a better Δ R / R response can be obtained with a thinner and narrower silicon piezoresistor. However, the S / N ratio was not significantly affected by the SiO 2 dimensions. A fabrication process of silicon covered SiO 2 microbridges is also reported.