We have investigated the deposition and electrochemical properties of sputtered ruthenium oxide coatings for neural stimulation and recording electrodes. A combination of oxygen and water vapor was used as a reactive gas mixture during DC magnetron sputtering from a ruthenium metal target. The sputtering plasma was monitored by optical emission spectroscopy to determine the reactive species present and confirm the control of plasma chemistry by reactive gas flow rates into the deposition chamber. The effect of the O₂:H₂O gas ratio on the microstructure and electrochemical properties of the ruthenium oxide were studied in detail. We employed a combination of surface characterization techniques, including scanning electron microscopy, x‐ray diffraction, and x‐ray photoelectron spectroscopy, to understand the relationship between plasma chemistry and the microstructure of the films produced under different gas flow conditions. Electrochemical characterization included cyclic voltammetry, electrochemical impedance spectroscopy, and voltage transient measurements, performed on planar ruthenium oxide electrodes with a geometric surface area of 1960 μm². At an O₂:H₂O gas flow rate ratio of 1:3, a cathodal charge‐storage capacity per unit film thickness of 228.7 mC cm⁻² μm⁻¹ (median, Q1 = 134.5, Q3 = 236.6, n = 15) and a charge‐injection capacity (0.6 V anodal interpulse bias) of 7.4 mC cm⁻² (median, Q1 = 6.9, Q3 = 8.3, n = 15) were obtained in phosphate buffered saline. The charge‐injection capacity of ruthenium oxide sputtered with water vapor in the reactive plasma is comparable with sputtered iridium oxide (SIROF) and higher than reported values for porous TiN, a commonly employed high‐surface area stimulation electrode coating.

中文翻译：

---

用于神经刺激和记录电极的溅射氧化钌涂层

我们研究了用于神经刺激和记录电极的溅射氧化钌涂层的沉积和电化学性能。在从钌金属靶材直流磁控溅射过程中，氧气和水蒸气的组合被用作反应性气体混合物。通过光学发射光谱监测溅射等离子体以确定存在的反应性物质并通过进入沉积室的反应性气体流速确认等离子体化学的控制。O ₂ :H _2的影响详细研究了O气比例对氧化钌微观结构和电化学性能的影响。我们采用了表面表征技术的组合，包括扫描电子显微镜、X 射线衍射和 X 射线光电子能谱，以了解等离子体化学与在不同气流条件下产生的薄膜微观结构之间的关系。电化学表征包括循环伏安法、电化学阻抗谱和电压瞬态测量，在几何表面积为 1960 μm ²的平面氧化钌电极上进行。在 O ₂ :H ₂ O 气体流量比为 1:3 时，每单位薄膜厚度的阴极电荷存储容量为 228.7 mC cm^-2 μm ^-1（中值，Q1 = 134.5，Q3 = 236.6，n = 15）和 7.4 mC cm ^-2的电荷注入容量（0.6 V 阳极脉冲间偏压） （中值，Q1 = 6.9，Q3 = 8.3，n = 15) 在磷酸盐缓冲盐水中获得。在反应等离子体中用水蒸气溅射氧化钌的电荷注入能力与溅射氧化铱 (SIROF) 相当，并且高于多孔 TiN（一种常用的高表面积刺激电极涂层）的报道值。