This paper reports a novel GaAs micromachined accelerometer based on the meso-piezoresistive effects of resonant tunneling diodes (RTDs). The sensitive unit of the accelerometer is the RTD which is located at the root of the beams. Based on the meso-piezoresistive effects of RTD, the accelerometer transduces acceleration into electrical signal output. This kind of accelerometer has been fabricated by GaAs IC surface processes and control hole etching technology. The output sensitivity and frequency characteristics of the accelerometer have been tested on the vibrating system. The result indicates that when the RTD is biased in the negative differential resistance region, the sensitivity of the suggested accelerometer is up to 90.51mV/g, and when biased in the positive resistance region, the sensitivity is 2.39 mV/g. It is obvious that the sensitivity in the negative resistance region is more one order higher than that in the positive resistance region, and the sensitivity of the accelerometer can be adjusted through changing the bias voltage. A frequency range of this structure as high as 1.5 KHz has also been achieved.

This letter reports a mesopiezoresistive effect in a double-barrier resonant tunneling (DBRT) structure. In a DBRT system, an external mechanical stress causes a tensile strain, and the strain, in turn, affects the resonant tunneling and thereby the resistance. Theoretical analysis was carried out on an AlAs/GaAs/AlAs DBRT structure under in-plane uniaxial tensile stresses. The results show that the tunneling current and resistance of a DBRT structure change significantly with external stress-induced tensile strains. The results also show that the resistance-strain response can be tuned effectively by the external voltage. The effect has potential applications in miniature electromechanical devices.