Fabrication and characterization of pressure sensor, and enhancement of output characteristics by modification of operating pressure range

Pressure microsensors are very frequently used for applications encompassing a wide range of operating pressure ranges. However, it is possible to use the same pressure sensor for different operating ranges (in a limited range) with satisfactory performance. In this work, we report the possibility of using a single sensor for different pressure ranges. Operating the sensor at a lower pressure range not only offers flexibility of usage but also enhances output performance in terms of sensitivity and linearity. The concept is demonstrated using a pressure sensor with implanted polysilicon piezoresistors and bulk micromachined diaphragm fabricated using a standard process. The characterization data of the sensor is analyzed for three pressure ranges (10 Bar, 20 Bar and 30 Bar). The results show that modifying the full scale pressure of operation from 30 to 10 Bar increases the sensitivity from 6.03 mV/Bar to 6.58 mV/Bar. The non-linearity is also reduced by an order of magnitude from 3.89 % to 0.33 %.