MEMS Electrostatic Energy Harvester Developed by Simultaneous Process for Anodic Bonding and Electret Charging

• Published in: Sensors and materials Vol. 35; no. 6; p. 1941
• Main Authors: Honma, Hiroaki, Ikeno, Sho, Toshiyoshi, Hiroshi
• Format: Journal Article
• Language: English
• Published: Tokyo MYU Scientific Publishing Division 01.01.2023
• Subjects: Bonding; Capacitance; Energy harvesting; High temperature; Parasitics (electronics); Silicon; SOI (semiconductors)
• DOI: 10.18494/SAM4402
• ISSN: 0914-4935

In this paper, we present a new structure and a process for electrostatic energy harvesters made in a silicon-on-glass wafer. Conventional electret-based MEMS energy harvesters are produced using a silicon-on-insulator (SOI) wafer, which is inevitably accompanied by parasitic capacitances across the buried oxide layer. The new harvester device, on the other hand, can be formed by individually developing silicon and glass parts and subsequently put together by anodic bonding, thereby virtually eliminating parasitic capacitance. Special caution is taken not to cause destruction of the electret layer during the high-temperature anodic bonding. The device has been successfully fabricated and experimentally confirmed to function as an energy harvester. This silicon-on-glass structure is beneficial in not only suppressing the parasitic capacitance but also increasing its output power compared with those made by the conventional SOI-based process