Use this URL to cite or link to this record in EThOS:
Title: MEMS : the fabrication of microsystems on silicon
Author: Daniel, J. H.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 1999
Availability of Full Text:
Full text unavailable from EThOS.
Please contact the current institution’s library for further details.
This thesis explores silicon MEMS in two areas, the field of physical sensors and MEMS in biotechnology. The emphasis is on simple fabrication, novel fabrication techniques, evaluation of recent silicon-based materials and up-to-date MEMS applications. First, bonded silicon-on-insulator material (SOI) and focused ion beam (FIB) processing are uniquely combined to fabricate microaccelerometer structures with a proof mass around 1-2x10-9 kg. Although FIB milling is widely used in the semiconductor industry, it is an unexplored technique for MEMS. Narrow readout gaps, milled obliquely into silicon beams, are investigated as a potential application for an economical FIB manufacturing process. Electron tunnelling and a novel 'tapping mode' are explored as sensitive readout mechanisms, based on these FIB milled gaps. Secondly, MEMS technology is exploited for a bioanalytical device. Micro reaction chambers, with volumes around 1-2 μL, for thermocycling solutions of biological reagents are fabricated in silicon using bulk micromachining. A special concept of thermally insulating the chambers from the surrounding wafer allows fast temperature cycling with time constants for cooling of the order of 0.5 seconds. Moreover, the power consumption for holding the liquid at 90°C is only around 1.8 Watt. This design is also promising for arrays for microcavities on one chip. The chambers are used to amplify DNA, the carrier of genetic information, employing the polymerase chain reaction (PCR).The advantages and drawbacks of silicon for this application are identified and possible alternatives described. The work presented in this thesis is an important contribution towards the lab-on-a-chip or towards a micro-total-analysis system (μ-TAS).
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available