High performance of silicon nanowire-based biosensors using a high-k stacked sensing thin film.

High performance silicon nanowire (SiNW) sensors with SiO2/HfO2/Al2O3 (OHA) engineered sensing thin films were fabricated. A lower interface state density, a larger capacitance and a stronger chemical immunity, which are essential for enhancing the performance of devices, were accomplished by stacking thin SiO2, HfO2, and Al2O3 layers, respectively, in sequence on the SiNW channel. Compared with the conventional single SiO2 thin film, the staked OHA thin films demonstrated improved sensing performances; a higher sensitivity, a lower hysteresis voltage, and a smaller drift rate, as well as a higher output current. Therefore, the SiNW sensors with OHA stacked sensing thin films are very promising to biological and chemical sensor applications.