We analyzed the low-frequency noise (LFN) of dual-gated field-effect transistor (DG-FET) biosensors with Schottky contacts. We found the flicker noise at the sensing insulator-semiconductor interface to be the major noise source while employing Schottky contacts to have minimal noise contribution with a sufficiently large back-gate bias voltage. The measured noise dependence on transconductance further indicated the presence of a nonuniform energy distribution of interface trap density at the said sensing interface. Based on these findings, we argued that the DG structure is advantageous over its single-gated (SG) counterpart; although they possess the same intrinsic lower limit of detection (LLOD), the former could offer a larger signal gain at the optimum LLOD thanks to sufficient channel carrier supply through back-gating instead of biasing the sensing interface toward band edge with higher trap density.

中文翻译：

---

肖特基接触双栅硅 FET 生物传感器的噪声性能研究


我们分析了具有肖特基接触的双栅极场效应晶体管 (DG-FET) 生物传感器的低频噪声 (LFN)。我们发现传感绝缘体-半导体界面处的闪烁噪声是主要噪声源，同时采用肖特基接触，在足够大的背栅偏置电压下将噪声贡献降至最低。测得的噪声对跨导的依赖性进一步表明在所述传感界面处存在界面陷阱密度的不均匀能量分布。基于这些发现，我们认为 DG 结构比单门控 (SG) 结构更有优势；尽管它们具有相同的固有检测下限 (LLOD)，但前者可以在最佳 LLOD 下提供更大的信号增益，这要归功于通过背栅提供充足的通道载流子供应，而不是将传感接口偏向具有更高陷阱密度的带边缘。