Peculiarities of the SCLC Effect in Gate‐All‐Around Silicon Nanowire Field‐Effect Transistor Biosensors

Abstract

AbstractHigh‐quality liquid gate‐all‐around (LGAA) silicon nanowire (NW) field‐effect transistor (FET) biosensors are fabricated and studied their properties in 1 mm phosphate‐buffered saline solution with pH = 7.4 using transport and noise spectroscopy. At small VDS, the conventional current behavior of FET with a linear dependence on voltage is registered in the output current‐voltage (I‐VM) characteristics with M = 1. At drain‐source voltage VDS > 0.6 V, the I‐V characteristics with stronger power M are revealed. It is shown that the current in LGAA NW FETs follows current proportional to voltage in power M = 4 dependence on small liquid gate voltages. Transport and noise spectroscopy analyses demonstrate that the obtained results are associated with the space‐charge‐limited current (SCLC) effect. Moreover, a strong two‐level random telegraph signal (RTS) is found in the region corresponding to SCLC at VDS values exceeding 0.6 V. The RTS related to single trap phenomena results in a well‐resolved Lorentzian component of noise spectra. The results demonstrate that the SCLC and two‐level RTS phenomenon are correlated effects. They should be taken into account during the development of single‐trap‐based devices, including biosensors.