Low-pressure measurement limits for silicon piezoresistive circular diaphragm sensors

Abstract

The lower limit to a practical measurable span is investigated for pressure sensors that have a silicon diaphragm with circular shape and employ piezoresistive gages. Output voltages and non-linearities of the sensors are analysed, taking into account the effects of the diaphragm's large deflection and the piezoresistive effect non-linearities. Based on this analysis and industrial requirements (the minimum span output voltage must be larger than 4.3 mV V-1 and non-linearities must be within +or-0.2% at the same time), it is found that the minimum span is 15 kPa.