Design And Optimisation Of Microelectroelectromechanical System (MEMS) Cochlear Biomodel

• Main Author: Ngelayang, Thailis Bounya
• Format: Thesis
• Language: English; English
• Published: 2016
• Subjects: T Technology (General); TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utem.edu.my/id/eprint/18180/1/Design%20And%20Optimisation%20Of%20Microelectroelectromechanical%20System%20%28MEMS%29%20Cochlear%20Biomodel%2024%20Pages.pdf; http://eprints.utem.edu.my/id/eprint/18180/2/Design%20And%20Optimisation%20Of%20An%20Adaptive%20Microelectromechanical%20System%20%28MEMS%29%20Cochlear%20Biomodel%20-%20cdr%2013888.pdf; http://eprints.utem.edu.my/id/eprint/18180/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=100082

The research and development of cochlear biomodelling has nowadays become one of the common interests in the biomedical research field. The main criterion of the developed cochlear biomodel is to have the ability to work within an audible range of human ear that is between 20 Hz to 20000 Hz. Microelectromechanical system (MEMS) is seen to have the potential to be utilised in mimicking the tonotopic organisation behavior of human ear. The developed MEMS cochlear biomodel is designed and simulated by using Comsol Multiphysics software to have the dimension of 0.5 μm thickness, 30 μm wide and length varying from 280 μm to 1000 μm. Five MEMS cochlear biomodel designs which are the Straight Bridge Beam (SBB), Straight Bridge Beam with Centered Diaphragm (SBBCD), Straight Bridge Beam with Centered Mass (SBBCM), Crab Legged and Serpentine, have been suggested in order to examine their resonant frequency performances. Four different materials have been considered which are Aluminium (Al), Copper (Cu), Tantalum (Ta) and Platinum (Pt). The design performance has been further tested in terms of its total surface displacement and capacitive ability. SBBCD MEMS cochlear biomodel that was developed with platinum as its base structure material and tantalum as the added mass material gives the highest resonant frequency performance of 92.87 % operating within the desired audible range. The design provides the total surface displacement ranging from 1.4370 nm to 0.0125 μm. The capacitance reading was also recorded to be 14.875 fF at the shortest beam structure and then increased to 53.125 fF towards the longest beam structure. In order to test its adaptivity, the structure was also tested with a voltage ranges from 0.1 V to 0.5 V. The resonant frequency tuning has been found to decrease in the range of 0.57 % to 4.65 % and the surface displacement has been amplified by ~4 to ~25 times bigger as the voltage increases. Relevant microfabrication steps have been suggested to fabricate SBBCM MEMS cochlear biomodel.