Control of channel doping concentration for enhancing the sensitivity of ‘top-down’ fabricated Si nanochannel FET biosensors
Control of channel doping concentration for enhancing the sensitivity of ‘top-down’ fabricated Si nanochannel FET biosensors
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控制通道掺杂浓度以增强“自上而下”制造的硅纳米通道 FET 生物传感器的灵敏度
作者：
C. Park;C. Ahn;Jong;I. Baek;C. Ah;A. Kim;Taeyoub Kim;G. Sung
定量分析了“自上而下”制造的硅纳米通道场效应晶体管（FET）生物传感器的灵敏度，作为通道宽度和掺杂浓度的函数。我们制作了130、150和220 nm宽的Si场效应管通道，并使用40 nm厚的p型绝缘体上硅（SOI）层掺杂在8 × 1017和2 × 1018 cm−3，并表征了它们作为氢离子传感器在不同pH值的缓冲溶液中响应表面电荷变化的灵敏度。在研究的通道宽度和掺杂浓度范围内，降低掺杂浓度比减小通道宽度更有效地提高了硅通道的pH灵敏度，这表明了一种比减小通道宽度更容易获得高灵敏度的实用策略。在前列腺特异性抗原（PSA）的免疫检测中也证实了类似的行为。结合通道结构优异的再现性和均匀性，掺杂浓度的高可控性可以使“自上而下”制造成为一种非常有用的方法，以经济有效的方式大规模制造高灵敏度传感器平台。
The sensitivity of ‘top-down’ fabricated Si nanochannel field effect transistor (FET) biosensors has been analyzed quantitatively, as a function of the channel width and doping concentration. We have fabricated 130-, 150-, and 220 nm-wide Si FET channels with 40 nm-thick p-type silicon-on-insulator (SOI) layers doped at 8 × 1017 and 2 × 1018 cm−3, and characterized their sensitivity in response to the variation of surface charges as hydrogen ion sensors within buffer solutions of various pH levels. Within the range of channel width and doping concentration investigated, the pH sensitivity of Si channels is enhanced much more effectively by decreasing the doping concentration than by reducing the channel width, which suggests a practical strategy for achieving high sensitivity with less effort than to reduce the channel width. Similar behavior has also been confirmed in the immunodetection of prostate specific antigen (PSA). Combined with excellent reproducibility and uniformity of the channel structure, high controllability of the doping concentration can make the ‘top-down’ fabrication a very useful approach for the massive fabrication of high-sensitivity sensor platforms in a cost-effective way.