Eung Seok Park

EECS Department, University of California, Berkeley

Technical Report No. UCB/EECS-2014-44

May 1, 2014

http://www2.eecs.berkeley.edu/Pubs/TechRpts/2014/EECS-2014-44.pdf

Printed electronics employing solution-processed materials is considered to be the key to realizing low-cost large-area electronic systems, but the performance of printed transistors is not generally adequate for most intended applications due to limited performance of printable semiconductors. In this dissertation, I propose an alternative approach of a printed switch, where the use of semiconductors can be avoided by building mechanical switches with printed metal nanoparticles. I provide the first demonstration of inkjet-printed micro-electro-mechanical (MEM) switches with abrupt switching characteristics, very low on-state resistance (~10 Ohm), and nearly perfect off-state behavior with immeasurable leakage with on/off current ratio of 10⁷. The devices are fabricated using a novel process scheme to build 3-dimensional cantilever structures from solution-processed metallic nanoparticles and sacrificial polymers. These printed MEM switches thus represent a uniquely attractive path for realizing printed electronics. I will also discuss an inkjet-printed microshell encapsulation as a new zero-level packaging technology. Inkjet-printing of silver nanoparticle ink is demonstrated to form porous microshells through which sacrificial oxide can be selectively removed to release MEMS structures. A second inkjet printing process using finer gold nanoparticle ink or polymer is demonstrated to effectively seal the microshells. This inkjet-printed microshell encapsulation technology is successfully applied to a MEM relay, and is demonstrated to mitigate the issue of contact oxidation. Specifically, the stability of the relay ON-state resistance is dramatically improved by more than a factor of 100.

Advisors: Tsu-Jae King Liu and Vivek Subramanian

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BibTeX citation:

@phdthesis{Park:EECS-2014-44,
    Author= {Park, Eung Seok},
    Title= {Application of Inkjet-Printing Technology to Micro-Electro-Mechanical Systems},
    School= {EECS Department, University of California, Berkeley},
    Year= {2014},
    Month= {May},
    Url= {http://www2.eecs.berkeley.edu/Pubs/TechRpts/2014/EECS-2014-44.html},
    Number= {UCB/EECS-2014-44},
    Abstract= {Printed electronics employing solution-processed materials is considered to be the key to realizing low-cost large-area electronic systems, but the performance of printed transistors is not generally adequate for most intended applications due to limited performance of printable semiconductors. In this dissertation, I propose an alternative approach of a printed switch, where the use of semiconductors can be avoided by building mechanical switches with printed metal nanoparticles. I provide the first demonstration of inkjet-printed micro-electro-mechanical (MEM) switches with abrupt switching characteristics, very low on-state resistance (~10 Ohm), and nearly perfect off-state behavior with immeasurable leakage with on/off current ratio of 10<sup>7</sup>. The devices are fabricated using a novel process scheme to build 3-dimensional cantilever structures from solution-processed metallic nanoparticles and sacrificial polymers. These printed MEM switches thus represent a uniquely attractive path for realizing printed electronics. I will also discuss an inkjet-printed microshell encapsulation as a new zero-level packaging technology. Inkjet-printing of silver nanoparticle ink is demonstrated to form porous microshells through which sacrificial oxide can be selectively removed to release MEMS structures.  A second inkjet printing process using finer gold nanoparticle ink or polymer is demonstrated to effectively seal the microshells.  This inkjet-printed microshell encapsulation technology is successfully applied to a MEM relay, and is demonstrated to mitigate the issue of contact oxidation. Specifically, the stability of the relay ON-state resistance is dramatically improved by more than a factor of 100.},
}

EndNote citation:

%0 Thesis
%A Park, Eung Seok 
%T Application of Inkjet-Printing Technology to Micro-Electro-Mechanical Systems
%I EECS Department, University of California, Berkeley
%D 2014
%8 May 1
%@ UCB/EECS-2014-44
%U http://www2.eecs.berkeley.edu/Pubs/TechRpts/2014/EECS-2014-44.html
%F Park:EECS-2014-44