Investigation on Piezoresistive Effect of n-Type 4H-SiC Based on All-SiC Pressure Sensors

Piezoresistive coefficients of materials are of great significance to the design of piezoresistance based devices. This paper proposed an in situ extraction method to determine the piezoresistive coefficients of n-type 4H-SiC, which requires no separate experimental study on the material properties and can directly obtain device-level parameters. Two types of all-SiC piezoresistive pressure sensors based on the SiC sealed cavity structure with different piezoresistor arrangements were fabricated and characterized. Through parameter fitting of the experimental data of pressure sensors and the numerical calculation results obtained by parameterization finite element analysis method, the longitudinal and transverse piezoresistive coefficients $\pi _{11}$ and $\pi _{12}$ that resulted in the best fit were found to be $- 3.4\times10$ ⁻¹¹ Pa ⁻¹ and $6.15\times10$ ⁻¹¹ Pa ⁻¹ , respectively. The extracted parameters were also verified to prove the reliability of the extraction method. The above research has significant value for the understanding of piezoresistive effect in materials and provides guidance for the design and performance optimization of SiC-based sensors.