Piezoresistive effect in GaAs/InxGa1−xAs/AlAs resonant tunneling diodes for application in micromechanical sensors

The current–voltage characteristics of GaAs/InxGa1−xAs/AlAs resonant tunneling diodes (RTDs) are a function of stress, and the current–voltage changes of RTDs with stress are attributed to the piezoresistive effect in RTDs. In order to study the piezoresistive effect in RTDs for application in micromachined mechanical sensors, the beam-mass structure based on RTDs is designed, fabricated and tested by the Wheatstone bridge test circuit. The test results show that the piezoresistive sensitivity of RTDs can be adjusted through the bias voltage, and the maximal piezoresistive sensitivity of RTDs with bias voltage at 0.618 V is 7.61×10−11 Pa−1, which is two orders higher than the minimal piezoresistive sensitivity (2.03×10−13 Pa−1) of RTDs with bias voltage at 0.656 V, and is also higher than the piezoresistive sensitivity of silicon material (5.52×10−11 Pa−1).