Multiplexed Silicon Nanowire Tunnel FET-Based Biosensors with Optimized Multi-Sensing Currents

In this study, silicon nanowire (SiNW) FET-based and SiNW tunnel FET (TFET)-based biosensors are co-integrated with CMOS circuits by using top-down approached and CMOS-compatible back-end process simultaneously. The possibility of multiplexed sensing is verified with the fabricated FET and TFET biosensors. For multiplexed-sensing, two separate sensing materials which react with two distinct bio-targets are formed by partially capping the gold on SiO2 film through a lift-off process. Then two bio-receptors which selectively combine to the gold and the SiO2 are deposited. After the reaction of each biomolecule to each receptor, the changes of saturation and gate-induced-drain-leakage (GIDL) currents are monitored in the FET sensor. It is experimentally confirmed that two different biomolecules are independently detectable by the changes of the saturation and the GIDL currents in the FET sensor. To solve the dependence of the gold formation position on the sensitivity as well as the large current difference between the saturation and the GIDL currents, we demonstrated the TFET biosensor which uses the changes of tunneling and ambipolar currents generated in the source and the drain end. As a result, it is clearly revealed that two different biomolecules can be detected without interference, regardless of the position of the gold layer by the changes of the tunneling and the ambipolar currents with almost equivalent sensing current level.