An investigation of the effects of doping and thickness on the electrical characteristics of polycrystalline silicon nanowire biosensors

Abstract

We study for the first time the effect of nanowire thicknesses and doping concentrations on the electrical characteristics of polycrystalline silicon nanowires to find out the proper combination of nanowire thickness and doping for sensitive operation of polycrystalline silicon nanowire biosensors. For nanowire thicknesses of 100 nm and 75 nm, a plausible subthreshold slope around 100 mV/dec for a viable biosensor operation can only be achieved if doping concentration is 2×1016/cm3 or below. For a 50 nm nanowire thickness a relatively wide doping concentration range can be chosen for biosensor design while maintaining decent sub-threshold characteristics. In this thickness a doping up to 4×1017/cm3 with a sub-threshold slope around 100 mV/dec can be chosen. The widest range of doping concentrations can be chosen for 25 nm and 10 nm nanowire thicknesses with a maximum doping up to 1018/cm3 while maintaining a promising sub-threshold slope around 95 mV/dec for a viable biosesnsor design using polycrystalline silicon nanowires. As such this research reveals the possible combinations of nanowire thickness and doping to ensure the sensitive operation of polycrystalline silicon nanowire biosensors.