High-Sensitivity InGaZnO FET Sensor Array With Offset Self-Calibration for Multibiomarker Sensing

This work proposes a dual-gate InGaZnO thin-film transistor sensor array for label-free and cross-scale multiple biomarkers detection, including single-stranded deoxyribonucleic acid (ssDNA) and protein CA125. We exploit dual gate modulation for threshold voltage and CMOS-based SAR-assisted digital-to-analog converter (DAC) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\text {BG}}$ </tex-math></inline-formula> calibration circuit to eliminate initial <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\text {TH}}$ </tex-math></inline-formula> offset variation caused by different functionalizations, which improve the reliability of the multibiomarker sensor array. At the same time, receptor enhancement on the indium gallium zinc oxide (IGZO) sensing membrane was detected by fluorescence assay, realizing higher sensitivity for biosensor. We demonstrate the sensor array response for pH in static and real-time mode, realizing near-Nernst limit sensitivity (55.02 mV/pH). Furthermore, at the top-gate configuration, with low operation voltage (0.1 V) and low offset variation (about 2 nA), the IGZO sensor array exhibits great performance for biomarker sensing which achieves sensitivity up to 4.426%/decade for ssDNA and 1102 nA/decade for CA125, with the limit of detection (LoD) of 1.67 aM for ssDNA and 0.1 fg/mL for CA125. This biosensor array provides a potential approach to realize miniaturization and high-density integration of multidimensional-biomarker detection.