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.

Automated summary

In this article, a rapid thermal process is proposed to manufacture piezoresistance for improved performance of piezoresistive devices. An absolute piezoresistive pressure sensor is prepared by anodic bonding between a silicon film and glass with a cavity, resulting in a compact size of 1.0 x 1.0 x 0.513 mm. The piezoresistance arrangement is optimized using the finite element method, and the feasibility of Ti as an oxygen absorber in the anodic bonding process is verified through diaphragm deformation measurement. The pressure sensor prepared using the rapid thermal annealing (RTP) process exhibits an output voltage of 91.6 mV, nonlinearity of 0.14% FSO, temperature coefficient of resistance (TCR) of 571 ppm/degrees C, and temperature coefficient of sensitivity (TCS) of -1676 ppm/degrees C within the pressure range of 0-200 kPa. Compared to the pressure sensor prepared by the common piezoresistive process, the designed sensor shows a reduced TCR by 73% and TCS by 24%, while providing high output voltage, low TCR and TCS, and a small size.