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Fabrication, structure, and performance of a microfabricated gallium electrical switch contact

Published online by Cambridge University Press:  26 August 2011

Yoonkap Kim ,
Julia A. Reid  and
David F. Bahr
Yoonkap Kim
Affiliation:
School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920
Julia A. Reid
Affiliation:
School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920
David F. Bahr*
Affiliation:
School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920
*
a)Address all correspondence to this author. e-mail: dbahr@wsu.edu
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Abstract

A contact for a micromechanical switch has been fabricated using electroplated gallium (Ga) on silicon to create an electrical switch contact that can be annealed to recover its original properties after mechanical damage. The resistivity of the electroplated Ga appears to be similar to pure Ga. The resistance increased with cycling but recovered to the original value after a thermal reflow process at 120 °C for 10 min. The hardness of thermally reflowed Ga droplets was 2 MPa when the droplets were unconstrained and was up to 95 MPa for constrained droplets, suggesting that all switching in this study caused permanent deformation at room temperature and that defects formed during plastic deformation are likely candidates for the increased resistance during cycling. Up to 300 switching cycles were investigated for contacts involving up to four Ga droplets to measure contact behavior under high-current and load-switching applications. Oxidation behavior was characterized for the thermal reflow process on the Ga droplets, suggesting a passivating 30-nm oxide form at 100 °C, and electrical contact resistance nanoindentation suggests the oxide breaks during mechanical contact.

Keywords

GaMetallic conductorMicroelectromechanical systems
Type
Articles
Information
Journal of Materials Research , Volume 26 , Issue 18 , 28 September 2011 , pp. 2428 - 2437
Copyright
Copyright © Materials Research Society 2011

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