A three-terminal silicon piezotransducer: general consideration and estimation of sensitivity

A general consideration of the three-terminal silicon piezotransducer (TTSP transducer) is described in the paper. The boundary problem is established and solved for the TTSP transducer with classic rectangular form of the current spread region (CSR), the analytical equations for potential distribution are obtained. The linear model of TTSP transducer presented in the paper allows us to describe the TTSP transducer as an external electrical circuit element, to calculate the difference between output currents and voltages on output contacts as a function of strain as well as the sensitivity of the transducer. The geometrical correction function is calculated in this paper for the considered classic rectangular form of the CSR. The sensitivity of the TTSP transducer is compared with the sensitivity of a four-terminal transducer with classic rectangular form. It follows from this comparison, that the four-terminal silicon transducer can be considered as a full analog of the piezoresistive Wheatstone bridge, whereas the TTSP transducer can be considered as an analog of a half-bridge circuit only.