Piezoresistive pressure sensor with Ladder shape design of piezoresistor

Abstract

In this study, a novel piezoresistor (PZR) design to improve the sensitivity of the piezoresistive type pressure sensor is reported. In this design, the PZR combined with various doping concentrations and doping depths is proposed and implemented. According to the design concept, the combined PZR which includes multiple piezoresistance coefficients would be arranged in a unique shape, just like a ladder. Theoretically, the sensitivity improvement could boost up to 15% based on this PZR design, even under the conditions of membrane edge offset due to fabrication processes. As a result, the sensitivity of the pressure sensor which adopted the Ladder shape PZR design is 0.058 mV/V/kPa. Moreover, the doping profile of the Ladder shape PZR is also extracted by SIMS. The serial measurements successfully prove the feasibility of this design concept. In the future, the presented PZR design can be further extended to various piezoresistive sensors, such as accelerometer, gyro, etc.