Wafer-scale fabrication of biologically sensitive Si nanowire FET: from pH sensing to electrical detection of DNA hybridization

In this work, a wafer-scale fabrication of biologically sensitive Si nanowire FET is demonstrated for pH sensing and electrical detection of DNA hybridization. Based on conventional “top-down” CMOS compatible technology, our bioFETs explore a wide range of design (nanowires [NW], nanoribbons [NR], and honeycomb [HC] structures) with opening access scaled down to only 120 nm. After device fabrication, I DS -V BG transfer and I DS -V DS output characteristics show a conventional n-type FET behavior with an I ON /I OFF value higher than 105, as well as an increase of threshold voltage as the NW width is reduced. Then, using a capacitive coupling in our dual-gated Si bioFETs, the pH sensitivity is enhanced with a pH response up to 600 mV/pH. Finally, the increase of threshold voltage of n-type SiNWs due to hybridized target DNA molecules is successfully detected.