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

Hui Fang, Jianing Zhao, Ki Jun Yu, Enming Song, Amir Barati Farimani, Chia Han Chiang, Xin Jin, Yeguang Xue, Dong Xu, Wenbo Du, Kyung Jin Seo, Yiding Zhong, Zijian Yang, Sang Min Won, Guanhua Fang, Seo Woo Choi, Santanu Chaudhuri, Yonggang Huang, Muhammad Ashraful Alam, Jonathan ViventiN. R. Aluru, John A. Rogers

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)11682-11687
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number42
StatePublished - Oct 18 2016


  • Chronic implant
  • Reactive molecular simulation
  • Thermal silicon dioxide
  • Thin-film encapsulation
  • Transfer printing

ASJC Scopus subject areas

  • General


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