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Proc Natl Acad Sci U S A. 2016 Oct 18;113(42):11682-11687.

Ultrathin, transferred layers of thermally grown silicon dioxide as biofluid barriers for biointegrated flexible electronic systems.

Author information

1
Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801; Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
2
Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801; Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
3
Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801; Department of Materials Science, Fudan University, Shanghai 200433, People's Republic of China.
4
Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
5
Department of Biomedical Engineering, Duke University, Durham, NC 27708.
6
School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907.
7
Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208; Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208.
8
Illinois Applied Research Institute, Urbana, IL 61820.
9
Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801; Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801; jrogers@illinois.edu.

Abstract

Materials that can serve as long-lived barriers to biofluids are essential to the development of any type of chronic electronic implant. Devices such as cardiac pacemakers and cochlear implants use bulk metal or ceramic packages as hermetic enclosures for the electronics. Emerging classes of flexible, biointegrated electronic systems demand similar levels of isolation from biofluids but with thin, compliant films that can simultaneously serve as biointerfaces for sensing and/or actuation while in contact with the soft, curved, and moving surfaces of target organs. This paper introduces a solution to this materials challenge that combines (i) ultrathin, pristine layers of silicon dioxide (SiO2) thermally grown on device-grade silicon wafers, and (ii) processing schemes that allow integration of these materials onto flexible electronic platforms. Accelerated lifetime tests suggest robust barrier characteristics on timescales that approach 70 y, in layers that are sufficiently thin (less than 1 μm) to avoid significant compromises in mechanical flexibility or in electrical interface fidelity. Detailed studies of temperature- and thickness-dependent electrical and physical properties reveal the key characteristics. Molecular simulations highlight essential aspects of the chemistry that governs interactions between the SiO2 and surrounding water. Examples of use with passive and active components in high-performance flexible electronic devices suggest broad utility in advanced chronic implants.

KEYWORDS:

chronic implant; reactive molecular simulation; thermal silicon dioxide; thin-film encapsulation; transfer printing

PMID:
27791052
PMCID:
PMC5081656
DOI:
10.1073/pnas.1605269113
[Indexed for MEDLINE]
Free PMC Article

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