title: Characterization of a-SiC(x):H thin films as an encapsulation material for integrated silicon based neural interface devices.
abstract: A fully integrated, wireless neural interface device is being developed to free patients from the restriction and risk of infection associated with a transcutaneous wired connection. This device requires a hermetic, biocompatible encapsulation layer at the interface between the device and the neural tissue to maintain long-term recording/stimulating performance of the device. Hydrogenated amorphous silicon carbide (a-SiC(x):H) films deposited by a plasma enhanced chemical vapor deposition using SiH(4), CH(4), and H(2) precursors were investigated as the encapsulation layer for such device. Si-C bond density, measured by Fourier transform infrared absorption spectrometer, suggests that deposition conditions with increased hydrogen dilution, increased temperature, and low silane flow typically result in increase of Si-C bond density. From the variable angle spectroscopic ellipsometry measurement, no dissolution of a-SiC(x):H was observed during soaking tests in 90°C phosphate buffered saline. Conformal coating of the a-SiC(x):H in Utah electrode array was observed by scanning electron microscope. Electrical properties were studied by impedance spectroscopy to investigate the performance of a-SiC(x):H as an encapsulation layer, and the results showed long term stability of the material.
authors.affiliation: Department of Material Science and Engineering, University of Utah, Salt Lake City, UT, USA.
authors.forename: Jui-Mei
authors.initials: JM
authors.lastname: Hsu
authors.forename: Prashant
authors.initials: P
authors.lastname: Tathireddy
authors.forename: Loren
authors.initials: L
authors.lastname: Rieth
authors.forename: A Richard
authors.initials: AR
authors.lastname: Normann
authors.forename: Florian
authors.initials: F
authors.lastname: Solzbacher