The Research Of The Micro Accelerometer Based On The Nano Field Effect Structure

In the paper, we carry out the study of the structrue of high sensitive sensors which basedon a nano field effect of structure. Theory is mainly micro-nano mechanical structuredeformation and the semiconductor devices carrier transport coupling mechanism research.Through the molecular dynamics method, we research the relationship betweensemiconductor devices cantilever beam and the internal stress reaction . In order to determinethe PHEMT i-v characteristics among the general rules of the stress modulation ,we researchthe internal stress of the cantilever beam influence of AlGaAs/GaAs PHEMT carriersconcentration and the heterojunction band structure . We have studied to determine theaccelerometer pressure resistance coefficient is 1 E-7, it high than the general piezo-resistivematerials two orders of magnitude. In addition, combined with micro processing technologyand the body surface processing techniques, we through the research of semiconductordevices embedded microstructure processing technology, design, processing and testing thePHEMT embedded microcontroller acceleration sensor structure. We work out the nano fieldeffect structure based on the high sensitive micro accelerometer. This paper, by usingmicro-cantilever beam structure, the macro forces will be introduced to the channel of thePHEMT. On this basis, we can make the coupling of the electric power sensor device, whichcan modulation of 2DEG’s concentration. Meanwhile ,we do the research work ofAlGaAs/GaAs-PHEMT output characteristic of the device . What we get results are shown asfollow:1. The molecular beam extension (MBE) technology preparation out DH-PHEMT film inthe 3 inches of GaAs substrate. On the film, we do the experiment for the X-raydiffraction map and Raman spectroscopy analysis. The atomic force microscopeobservation to that the surface of the film is smooth. The film’s roughness is less than0.72 nm within the scope of 2μm x 2μm. 2. Put forward the concept of nano field effect structure. When the channel length andmaterial layer structure to narrow the nanometer scale, and the power supply voltage anddevice size not at the same rate reduced to nanometer level, these changes will make theinternal components of the electric field to change. With the increasing electric field, andthe physical properties of high voltage basic change, its quantum effect to the device willaffect performance.3. This paper designed the DH-PHEMT devices and micro-cantilever beam themicrostructure of the integration. Through the processing of the key technology in theprocess of the research, we use the control hole technology is precise control of thequality and cantilever beam thickness. Based on the relevant process experiment, wefinished the DH-PHEMT device and microstructure trial, the result showed that in thecantilever beam root of the DH-PHEMT device of the largest by stress, and when thechannel direction parallel with the direction of the cantilever beam we got the highestsensitivity, and this is in accordance with the design idea and the simulation results.4. The output characteristic test results of the GaAs DH-PHEMT devices are shown:DH-PHEMT devices in the high temperature and low temperature testing device outputsaturated current follow I∝T-1 (200 K < T < 320 K) change trend; DH-PHEMT deviceoutput current decrease with the tensile stress and increase with the pressure of stress.And on the stress sensitivity can reach 9.27 mV/g, linearity for 0.11.To sum up, this paper complete GaAs DH-PHEMT device and microstructure ofintegration design and processing, analysis the temperature and stress for the DH-PHEMTdevice output characteristics influence. Set up the DH-PHEMT device GaAs outputcharacteristic model, the microstructure of inertia test laid the foundation for further study.