Microchip-Embedded Capacitors for Implantable Neural Stimulators
Miniaturization of microchips for implantation in the human body (e.g., microchip for the artificial retina to restore sight to people blinded by retina photoreceptors degeneration) requires the integration of high-capacitance (≥ 10 μF) energy-storage capacitors into the microchip. These capacitors would be based on high-dielectric constant layers, preferably made of materials that are bioinert (not affected by human body fluids) and are biocompatible (do not elicit adverse reactions in the human body). This chapter focuses on reviewing the work being done at Argonne National Laboratory (Materials Science Division and Center for Nanoscale Materials) to develop high-capacitance microchip-embedded capacitors based on novel high-K dielectric layers (TiAlOx or TiO2/Al2O3 superlattices). The microchip-embedded capacitor provides energy storage and electromagnetic signal coupling needed for neural stimulations. Advances in neural prostheses such as artificial retinas and cochlear implants require miniaturization of device size to minimize tissue damage and improve device/tissue interfaces in the human body. Therefore, development of microchip-embedded capacitors is critical to achieve full-implantable biomedical device miniaturization.
KeywordsAtomic Layer Deposition Cochlear Implant High Dielectric Constant Gate Oxide Important Electronic Device
The author wishes to acknowledge support from the U. S. Department of Energy, BES-Materials Science for work in the Materials Science Division, under contract W-31-109-ENG-38. The work at the Center for Nanoscale Materials and at the Electron Microscopy Center for Materials Research at Argonne National Laboratory was supported by the U.S. Department of Energy-Office of Science under Contract No. DE-AC02-06CH11357 by U Chicago Argonne, LLC. The author also acknowledges the many colleagues and postdoctorals who have made substantial contributions to the work discussed in this chapter over the years, namely: J.A. Carlisle, W. Fan, B. Kabius, R. Baragiola, and E.A. Irene.
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