Both polysilicon bridge and beam resonators have been fabricated and characterised. In addition, a CMP planarisation based process has been used to demonstrate a fabrication platform for producing micromechanical resonators with submicron transducer gaps. This process requires one photolithographic step less than previously reported fabrication methods and does not suffer from transducer gap widening, which otherwise strongly affects the impedance of manufactured resonators. As part of this work, pattern dependent removal rates for polysilicon have been determined and design guidelines defined to optimise the yield of CMP fabricated resonators. FIB Pt deposition on both bridge and beam resonators has been used to demonstrate location dependent bidirectional frequency tuning (-19% to +18%). In contrast to competing technologies, such as laser trimming, FIB deposition does not cause device damage. Its advantage is that it is performed at room temperature, does not require any sample preparation and no power is consumed to maintain the trimmed frequency. Real time electrochemical Ag deposition has been demonstrated to be capable of tuning polysilicon bridge resonators. It showed a location dependent bidirectional frequency change (-10% to +10.7%) using minimal power (20nW). This was implemented using an Ag deposition scheme consisting of a solid electrolyte, an Ag anode and Al contacts, and was integrated into bridge resonators using evaporation and shadow mask techniques. The advantage of this method over FIB Pt deposition is that it can provide dynamic in-situ simultaneous tuning of many resonators on the same chip.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:650021 |
| Date | January 2006 |
| Creators | Enderling, Stefan |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14795 |
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