Modal Analysis of Gallium Nitride Membrane for Pressure Sensing Device
| Autor: | M. Vallo, Tibor Lalinský, M. Držík, J. Dzuba, Gabriel Vanko, Vladimír Kutiš, Ivan Rýger |
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| Rok vydání: | 2014 |
| Předmět: |
Materials science
business.industry Mechanical Engineering Modal analysis Analytical chemistry Natural frequency Gallium nitride High-electron-mobility transistor Finite element method Stress (mechanics) chemistry.chemical_compound Membrane chemistry Mechanics of Materials Residual stress Optoelectronics General Materials Science business |
| Zdroj: | Key Engineering Materials. 605:404-407 |
| ISSN: | 1662-9795 |
| DOI: | 10.4028/www.scientific.net/kem.605.404 |
| Popis: | A circular high electron mobility transistor (C-HEMT) prepared on the AlGaN/GaN membrane surface has been investigated and its potential for pressure sensing has been already demonstrated. The key issue in the design process of such heterostructure based MEMS sensors is the stress engineering. This way we can scale the sensor performance, measured pressure range and sensitivity. Especially, the knowledge of the exact value of the residual stress in membranes (caused by deposition process) helps us to optimize the sensing devices. In this work, the residual stress determination method in gallium nitride circular shaped membrane is reported. It is shown that resonant frequency method using Laser Doppler Vibrometry (LDV) for membrane vibration measurement seems to be an appropriate technique to determine the residual stress in micro-scale membranes. Circularly shaped AlGaN/GaN micro-membranes are excited by acoustic short time pulse. The decay oscillating motion of the membrane is recorded by oscilloscope. By FFT spectral analysis of the signals the resonance frequencies are obtained. For the sample studied, the natural frequency mode resonance peak is used to define the residual stress level. To verify the observed stress in investigated membranes, prestressed modal analysis in finite element method (FEM) code ANSYS is performed. The stress extracted from the measured frequency is taken as an initial stress state of the modelled membrane. Experimentally obtained shock spectra are compared with that computed by FEM simulation. |
| Databáze: | OpenAIRE |
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