Low-impedance thin-film polycrystalline silicon microelectrodes for extracellular stimulation and recording

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• 作者：Bucher ; Volker ; Graf ; Michael ; Stelzle ; Martin ; Nisch ; Wilfried
• 关键词：Impedance spectroscopy ; Micro electrode arrays ; Polycrystalline silicon ; Porous silicon ; Thin-film microelectrodes
• 刊名：Biosensors and Bioelectronics
• 出版年：1999
• 出版时间：October, 1999
• 年：1999
• 卷：14
• 期：7
• 页码：639-649
• 全文大小：3.53 M

文摘

Polycrystalline silicon thin films were explored with respect to their application as low-impedance microelectrodes for extracellular stimulation and recording of cells. Microelectrode arrays (MEAs) comprising polysilicon microelectrodes were fabricated using CMOS-compatible processes. Overall capacitance of an electrode with a diameter of 20 μm is on the order of 200–300 pF. Chemical and morphological stability in physiological saline solution was excellent over a period of at least 5 months. This finding renders applications in neuronal implants or bio-chips. Nanoporous polysilicon electrodes were created by anodic oxidation in hydrofluoric acid (HF). However, no considerable decrease of electrode impedance was observed although pore formation was clearly confirmed by transmission electron microscopy (TEM).