Design and fabrication of a bulk micromachined accelerometer for geophysical applications

Droogendijk, Harmen (2009) Design and fabrication of a bulk micromachined accelerometer for geophysical applications.

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Abstract:Using gravitational acceleration (gravity) or its gradient, geophysicists are capable of determining the presence of gas and oil. These gravitational effects are often very small compared to earth’s gravity (typically less than 1:100.000), making measurements rather difficult. Although nowadays measurement systems are present for gravity (gradient) sensing, the use of MEMS (Micro Electro Mechanical Systems) is quite rare within this field. Realization of such a sensor in MEMS would offer various benefits. These possibilities are investigated, resulting in the design and fabrication of a bulk micromachined accelerometer for geophysical applications. Before designing this accelerometer, first gravity and its gradient itself are investigated. Most commonly used measurement techniques are determined, resolutions are researched and the applicability within MEMS is summarized. From these results a very sensitive MEMS accelerometer is designed and several effects, restraints, read-out mechanisms and optimization methods are investigated. Using bulk micromachining and sidewall coating technology, a process is developed to fabricate such a sensor. Several sensors for geophysical applications are fabricated, leading to important information regarding the fabrication process. Despite the fabrication of the sensors, the process is not robust enough for characterization of the devices. However, using numerical analysis combined with computer simulations, several predictions about the performance of such a MEMS sensor is given, which gives important results regarding the use and opportunities of MEMS in the gravitational field.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:53 electrotechnology
Programme:Electrical Engineering MSc (60353)
Link to this item:http://purl.utwente.nl/essays/68937
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