Design and Analysis of High-Performance and Small-Size Piezoresistive Pressure Sensors

In this article, a rapid thermal process is proposed to manufacture piezoresistance to improve the performance of piezoresistive devices, and an absolute piezoresistive pressure sensor is prepared by anodic bonding between silicon film and glass with the cavity to reduce the size of the device. The size of the sensor is only 1.0 x 1.0 x 0.513 mm. At the same time, the arrangement of piezoresistance is optimized by the finite element method. In addition, the deformation of the diaphragm is measured with a profiler, which verified the feasibility of Ti as the absorption of oxygen generated in the anodic bonding process. In the pressure range of 0-200 kPa, the output voltage and nonlinearity of the pressure sensor prepared by the rapid thermal annealing (RTP) process are 91.6 mV and 0.14%FSO, respectively, and the temperature coefficient of resistance (TCR) and the temperature coefficient of sensitivity (TCS) are 571 and -1676 ppm/degrees C respectively. Compared with the pressure sensor prepared by the common piezoresistive process, the TCR and TCS of the designed sensor are reduced by 73% and 24%, respectively, which has the advantages of high output voltage, low TCR and TCS, and small-size.