On Noise Performance of Dual-Gated Silicon FET Biosensors With Schottky Contacts

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.

Automated summary

The study analyzed the low-frequency noise of dual-gated field-effect transistor biosensors with Schottky contacts, finding that the flicker noise at the sensing insulator-semiconductor interface was the major noise source. Additionally, the research suggested that the DG structure offers advantages over its single-gated counterpart in terms of signal gain.