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Design and fabrication of a micro-opto-mechanical-systems accelerometer based on intensity modulation of light fabricated by a modified deep-reactive-ion-etching process using silicon-on-insulator wafer

Gholamzadeh, R ; Sharif University of Technology | 2022

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  1. Type of Document: Article
  2. DOI: 10.1116/6.0001779
  3. Publisher: AVS Science and Technology Society , 2022
  4. Abstract:
  5. Accelerometers that work based on intensity modulation of light are more sensitive, economically feasible, and have a simpler fabrication process compared to wavelength modulation. A micro-opto-electro-mechanical-system accelerometer based on intensity modulation of light is designed and fabricated. A movable shutter that is attached to the proof mass is designed to change the intensity of light. Moreover, the mechanical part is designed to improve the overall sensitivity and linear behavior in the measurement range. The designed accelerometer is fabricated by a deep-reactive-ion-etching (DRIE) process. The DRIE process used in this report is based on a Bosch-like process, which uses SF 6 and a mixture of H 2, O 2, and SF 6 gases in etching and passivation subsequences, respectively. This method has a lower plasma density and a higher base pressure and causes higher verticality, which results in lower optical efficiency loss in comparison with the Bosch process. Furthermore, the functional characteristics of the accelerometer are derived with analytical and numerical methods, and the results are compared. The functional characteristics of the accelerometer are as follows: a resonant frequency of 0.56 kHz, a mechanical sensitivity of 0.6 μ m / g, an optical sensitivity of 16 % / nm, an overall sensitivity of 9.6 % / g, a footprint of 2000 × 2000 μ m 2, a measurement range of 3 g, a mechanical cross axis sensitivity of 0.058 μ m / g, and an overall cross axis sensitivity of 0.000 29 % / g. These functional characteristics make the design appropriate for a large range of applications. © 2022 Author(s)
  6. Keywords:
  7. Accelerometers ; MEMS ; Modulation ; Natural frequencies ; Numerical methods ; Plasma density ; Reactive ion etching ; Silicon on insulator technology ; Silicon wafers ; Cross-axis sensitivity ; Deep Reactive Ion Etching ; Deep reactive-ion etchings ; Etching process ; Functional characteristics ; Intensity modulations ; Measurement range ; Opto-mechanical systems ; Silicon on insulator wafers ; Simple++ ; Fabrication
  8. Source: Journal of Vacuum Science and Technology B ; Volume 40, Issue 4 , 2022 ; 21662746 (ISSN)
  9. URL: https://pubs.aip.org/avs/jvb/article-abstract/40/4/043001/2845657/Design-and-fabrication-of-a-micro-opto-mechanical?redirectedFrom=fulltext