Cantilever surface stress sensors with single-crystalline silicon piezoresistors

We present a cantilever with piezoresistive readout optimized for measuring the static deflection due to isotropic surface stress on the surface of the cantilever [Sens. Actuators B 79(2-3), 115 (2001)]. To our knowledge nobody has addressed the difference in physical regimes, and its influence on cantilever sensors with integrated piezoresistive readout, that one finds between typical atomic force microscopy measurements and the surface stress sensors used in, e.g., biochemical measurements. We have simulated the response from piezoresistive cantilevers as a function of resistor type and placement for the two different regimes, i.e., surface stress measurements and force measurements. The model thus provides the means to specifically design piezoresistive cantilevers for surface stress measurements. (c) 2005 American Institute of Physics.