MOS transistor pressure sensor

摘要

An expression that describes the behavior of the channel mobility of a metal oxide semiconductor transistor (MOST) under pressure, longitudinally oriented with respect to the edge of a silicon square diaphragm, used as a pressure sensor, is derived. This expression is incorporated into PSPICE, to allow the modeling of transistors under pressure, by means of this conventional simulator. An integrated readout circuit consisting of four active MOST, four dummy MOST and two differential amplifiers is presented, which provides a linear variation dependence between pressure and output voltage, for pressures between 0 and 100 kPa, with an output of 250 mV at maximum pressure. This circuit also provides compensation for the output voltage dependence on temperature and channel misalignment with respect to the edge of the diaphragm.