Piezoresistivity Study in ${\rm Al}_{\rm x}{\rm Ga}_{1-{\rm x}}{\rm As}$ Thin Film for Sensor Application at Room Temperature

In this letter, we report the piezoresistive effect at room temperature of a Al_xGa_1-xAs thin film, which has been integrated on the beams of an accelerometer as sensing elements to detect the external strain. The Al_xGa_1-xAs piezoresistive thin film was grown by metal organic chemical vapor deposition (MOCVD) on a semi-insulating (001) GaAs substrate. And the GaAs-based piezoresistive accelerometer has been processed with advanced surface micromachining processes and GaAs bulk micromachining processes. The measurements of piezoresistive properties were performed for tensile strains by static experiments. The measured maximum gauge factor G (ΔR/R = Gε) for the AlGaAs thin film can be estimated to 70. Meanwhile, the dynamic experiments showed the sensor response.