標題: A CMOS 256-pixel Photovoltaics-powered Implantable Chip with Active Pixel Sensors and Iridium-oxide Electrodes for Subretinal Prostheses
作者: Wu, Chung-Yu
Kuo, Po-Han
Lin, Po-Kang
Chen, Po-Chun
Sung, Wei-Jie
Ohta, Jun
Tokuda, Takashi
Noda, Toshihiko
電機學院
電機工程學系
College of Electrical and Computer Engineering
Department of Electrical and Computer Engineering
關鍵字: divisional power supply scheme;active pixel sensor;photovoltaic cell;CMOS image sensor;biocompatible package
公開日期: 1-Jan-2018
摘要: A CMOS implantable chip with 256 active pixel sensors (APSs), on-chip photovoltaic cells, and iridium-oxide (IrOx) electrodes is proposed and designed for subretinal prostheses. In the proposed chip, the on-chip electrode surface is deposited with IrOx by RF sputtering and photolithography patterning. The divisional power supply scheme (DPSS) is adopted to generate sufficient stimulation current whereas the APS is used to enhance the image sensitivity. The proposed chip consists of a 16 x 16 photodiode array with 8 DPSS divisions, control signal generator circuits, and photovoltaic cells. It is designed and fabricated into 180 nm CMOS image sensor (CIS) technology and postprocessed with an IrOx coating. From the electrical measurement results, the fabricated chip has a peak output stimulation current of 16.7 mu A under the equivalent electrode impedance load. The stimulation frequency is 30.2 Hz and the amount of injected charges at each pixel is 3.5 nC. Both image light sensitivity and injection charges are significantly improved. The surface morphology, crystallinity, charge storage capacity, and biocompatibility of sputtering iridium oxide film (SIROF) were investigated. As a result, the SIROF has desirable physical and electrochemical properties that make it suitable for the neurostimulation electrodes on the 256-pixel implantable chip. The 7-month biocompatibility and charge delivery capability of the fabricated chip have been confirmed by electroretinography (ERG) measurement on a Lanyu minipig in in vivo animal tests.
URI: http://dx.doi.org/10.18494/SAM.2018.1664
http://hdl.handle.net/11536/144932
ISSN: 0914-4935
DOI: 10.18494/SAM.2018.1664
期刊: SENSORS AND MATERIALS
Volume: 30
起始頁: 193
結束頁: 211
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