Piezoresistive Sensing of Bistable Micro Mechansim State

The objective of this work is to demonstrate the feasibility of on-chip sensing of bistable mechanism state using the piezoresistive properties of polysilicon, thus eliminating the need for electrical contacts. Changes in position are detected by observing changes in resistance across the mechanism. Sensing the state of bistable mechanisms is critical in their various applications. The research in this thesis advances the modeling techniques of MEMS devices which use piezoresistivity for position sensing. A fully compliant bistable micro mechanism was designed, fabricated, and tested to demonstrate the feasibility of this sensing technique. Testing results from two fabrication processes, Fairchild's SUMMiT IV and MUMPs, are compared. The Fairchild mechanism was then integrated into various Wheatstone bridge configurations to show the advantages of bridges and to demonstrate various design layouts. Repeatable and detectable results were found with independent mechanisms and with those integrated into Wheatstone bridges. Finite element models were constructed for the different Wheatstone bridges which were used to predict piezoresistive trends. A bistable mechanism for high-acceleration sensing was designed using uncertainty analysis optimization. The piezoresistive effects for this mechanism were also modeled. Discussion concerning nonvolatile memory applications is also presented.

Name thesis:degree_name

MS

Grantor dc:publisher

Brigham Young University - Provo

Author dc:creator

• Anderson, Jeffrey K.

• MEMS
• micro
• bistable
• mechanism
• piezoresistivity
• piezoresistive
• piezo
• sensing
• compliant
• polysilicon
• state
• Mechanical Engineering

Language dc:language

English

Repository record dc:identifier

https://scholarsarchive.byu.edu/etd/692

OAI identifier oai:identifier

oai:scholarsarchive.byu.edu:etd-1691