Study Of GaAs-Based Resonant Tunneling Piezoresistor Accelerometer

This thesis reports a novel piezoresistor accelerometer, the sensitivity may be higher oneorder than silicon micro-accelerometer. The accelerometer is based on Meso-piezoresistanceeffect of GaAs/AlAs RTD (Resonant Tunneling Diodes). The applied acceleration on the proofmass induces stress in the layers of the RTD , which will induce change in the electrons effectivemass and the generated piezoelectric fields inside the well and the barrier materials. Then theenergy states will also change.These variations will change the peak current and voltage of theRTD. It looks like a change in electrical resistance of RTD when subjected to stress fields.The thesis introduces the principle, structure and techniques design of the GaAspiezoresistor accelerometer in details. The basic structures of accelerometer is imitated andanalyzed by Ansys finite element software and mechanics theory, then the final structure isdesigned. For the structure, we establish the techniques of the GaAs piezoresistor accelerometer,which includes MBE (Molecular Beam Epitaxy) technology, surface and bulk micromachining processes.Autoeciousness capacitance is reduced by using air bridge technology and the beam-massstructure of accelerometer is machined via control hole technique. According to the process flow,the drawing is designed and the accelerometer is machined. Finally, the accelerometer is testedand analyzed, acceleration signal has been find.The thesis reports the key study result as follows:1. Using Meso-piezoresistance effect of RTD as the principle of a novel accelerometer inthe first.2. The RTD was fabricated by using air bridge technology, then the autoeciousnesscapacitance is reduced.3. GaAs-based MEMS microstructure is machined, then the accelerometer is tested and getthe acceleration signal.