Improved sensitivity of nanowire bio-FETs operated at high-frequency: a simulation study

Silicon Nanowire (SiNW) Bio-FETs emerged as promising candidates for DNA and proteins detection, but static screening severely limits the response to analytes located beyond approximately one Debye length from the surface. In this paper we investigate for the first time the potential advantages of the small signal response of SiNW Bio-FETs in wet environment and up to frequency above the electrolyte’s dielectric relaxation cut-off frequency by means of three-dimensional simulations calibrated on experiments. We find that the static Debye screening limit is overcome at high frequency, where the change in capacitance due to the analyte binding is weakly sensitive on distance from electrode, salt concentration and hardly controllable surface charges.