title: Ultrathin, transferred layers of thermally grown silicon dioxide as biofluid barriers for biointegrated flexible electronic systems.
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 SiO2and surrounding water. Examples of use with passive and active components in high-performance flexible electronic devices suggest broad utility in advanced chronic implants.
authors: 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.
authors: Hui
authors: H
authors: Fang
authors: 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.
authors: Jianing
authors: 0000-0002-0023-7388
authors: J
authors: Zhao
authors: 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.
authors: Ki Jun
authors: KJ
authors: Yu
authors: 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.
authors: Enming
authors: E
authors: Song
authors: Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
authors: Amir Barati
authors: AB
authors: Farimani
authors: Department of Biomedical Engineering, Duke University, Durham, NC 27708.
authors: Chia-Han
authors: CH
authors: Chiang
authors: School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907.
authors: Xin
authors: X
authors: Jin
authors: Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208; Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208.
authors: Yeguang
authors: 0000-0002-1968-5092
authors: Y
authors: Xue
authors: 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.
authors: Dong
authors: D
authors: Xu
authors: Illinois Applied Research Institute, Urbana, IL 61820.
authors: Wenbo
authors: W
authors: Du
authors: 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.
authors: Kyung Jin
authors: KJ
authors: Seo
authors: 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.
authors: Yiding
authors: Y
authors: Zhong
authors: 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.
authors: Zijian
authors: Z
authors: Yang
authors: 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.
authors: Sang Min
authors: SM
authors: Won
authors: 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.
authors: Guanhua
authors: G
authors: Fang
authors: 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.
authors: Seo Woo
authors: SW
authors: Choi
authors: Illinois Applied Research Institute, Urbana, IL 61820.
authors: Santanu
authors: S
authors: Chaudhuri
authors: Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208; Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208.
authors: Yonggang
authors: Y
authors: Huang
authors: School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907.
authors: Muhammad Ashraful
authors: MA
authors: Alam
authors: Department of Biomedical Engineering, Duke University, Durham, NC 27708.
authors: Jonathan
authors: J
authors: Viventi
authors: Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
authors: N R
authors: NR
authors: Aluru
authors: 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.
authors: John A
authors: JA
authors: Rogers
mesh_terms: D001826:Body Fluids; D003198:Computer Simulation; D004560:Electricity; D004582:Electronics, Medical; D008962:Models, Theoretical; D012822:Silicon Dioxide / Q000737:chemistry; D013696:Temperature
chemical_list: D012822:Silicon Dioxide
keywords: chronic implant; reactive molecular simulation; thermal silicon dioxide; thin-film encapsulation; transfer printing