Comparison of sensitivity between the FTSP transducers and piezoresistive wheatstone bridge

This paper presents the comparison of sensitivity between four-terminal silicon piezotransducers (FTSP transducers) and piezoresistive bridge. This comparison is carried out for the transducer fabricated on the silicon diaphragm with crystal plane [100] and n type of conductivity. It was suggested that the current spread region (CSR) of FTSP transducer have p type of conductivity, the thickness of sensitive layer is much less than the thickness of the diaphragm, the CSR is placed near the edge of diaphragm and rotated by the angle of 45/spl deg/ with respect to the diaphragm, the planer sizes of transducer is much less than the planer sizes of diaphragm. In our paper it´s shown that the sensitivity of each FTSP transducer supplied with the current source is equal in extreme case. If voltage source is used, the bridge have the greatest sensitivity if all piezoresistors are small and located near the edge of the diaphragm. It´s shown that the sensitivity of FTSP transducer consists 0.75 and 0.4678 of sensitivity of the piezoresistive bridge for rectangular CSR and nonrectangular CSR, respectively. However, the FSTP transducer have the more simple topology and can be more effective for very small silicon chips.