Noise Characterization of Semiconductor Nanowires

Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2016

A method to envisage trap density in the semiconductor bandgap near the semiconductor/oxide interface of nanoscale silicon junctionless transistors (JLTs) is presented. JLTs are fabricated in a bottom-up fabrication technique using in situ highly doped nanowires grown by low pressure chemical vapor deposition. Low-frequency noise characterization of JLTs biased in saturation is conducted at different gate biases. The noise spectrum indicates either a Lorentzian or 1/f noise depending on the gate bias. Analysis of the results indicates very low trap densities in the order of 10 16 cm À3 eV À1. Low trap densities in these devices are associated with their simple fabrication technique, in situ oxide formation, and the absence of semiconductor junction and the ion implantation step in the process. A simple analysis of the low-frequency noise data leads to the density of the traps and their energy within the semiconductor bandgap and their location from the Si/SiO 2 interface. V

Journal of Applied Physics, 2013

IEEE Electron Device Letters, 2009

The low-frequency noise (LFN) in the subthreshold region of both n-and p-type gate-all-around silicon nanowire transistors (SNWTs) is investigated. The measured drain-current noise spectral density shows that the LFN in this regime can be well described by the mobility-fluctuation model due to the volume-inversion conduction behavior, and the Hooge parameter is extracted. The LFN in the SNWTs with channels oriented in 010 and 110 directions is compared. It shows that the observed mobility enhancement in the 010 direction for p-type transistors leads to a corresponding increase of the LFN level in the 010 direction compared with that in the 110 direction.

Keywords: 1/f noise Silicon nanowire sensor Ion sensitive field effect transistor Noise source a b s t r a c t We analyzed 1/f noise in silicon nanowire ion-sensitive field-effect transistors (SiNW-ISFETs) having different wire widths ranging from 100 nm to 1 m and operated under different gating conditions in order to determine the noise source and the sensor accuracy. We find that the gate-referred voltage noise S VG (power spectral density) is constant over a large range of SiNWs resistances tuned by a DC gate voltage. The measurements of S VG for SiNWs with two different gate-oxide thicknesses, but otherwise similar device parameters, are only compatible with the so-called trap state noise model in which the source of 1/f noise is due to trap states residing in the gate oxide (most likely in the interface between the semiconductor and the oxide). S VG is found to be inversely proportional to the wire width for constant wire length. From the noise data we determine a sensor accuracy of 0.017% of a full Nernstian shift of 60 mV/pH for a SiNW wire with a width of 1 m. No influence of the ions in the buffer solution was found.

IEEE Electron Device Letters, 2000

The low-frequency (1/f ) noise of gate-all-around silicon nanowire transistors (SNWTs) with different gate electrodes (poly-Si gate, doped fully silicided (FUSI) gate, and undoped FUSI gate) is studied in the strong-inversion linear region. It shows that the gate electrodes have a strong impact on the 1/f noise of the SNWTs. The highest noise is observed in the SNWTs with a poly-Si gate, compared to their FUSI-gate counterparts. The observations are explained according to the number fluctuation with correlated mobility fluctuation theory by assuming that the correlated mobility scattering is better screened in the case of an undoped FUSI gate. However, the doped FUSI gate with silicidation-induced impurity segregation at the gate/SiO 2 interface gives rise to extra mobility scattering.

2010

Flicker or 1/f noise in metal-oxide-semiconductor field-effect transistors (MOSFETs) has been identified as the main source of noise at low frequency. It often originates from an ensemble of a huge number of charges trapping and detrapping. However, a deviation from the wellknown model of 1/f noise is observed for nanoscale MOSFETs and a new model is required. Here, we report the observation of one-by-one trap activation controlled by the gate voltage in a nanowire MOSFET and we propose a new low-frequency-noise theory for nanoscale FETs. We demonstrate that the Coulomb repulsion between electronically charged trap sites avoids the activation of several traps simultaneously. This effect induces a noise reduction by more than one order of magnitude. It decreases when increasing the electron density in the channel due to the

Applied Physics Letters, 2008

Single ZnO nanowire ͑NW͒ transistors fabricated with self-assembled nanodielectric ͑SAND͒ and SiO 2 gate insulators were characterized by low-frequency noise and variable temperature current-voltage ͑I-V͒ measurements. According to the gate dependence of the noise amplitude, the extracted Hooge's constants ͑␣ H ͒ are ϳ3.3ϫ 10 −2 for SAND-based devices and ϳ3.5ϫ 10 −1 for SiO 2 -based devices. Temperature-dependent I-V studies show that the hysteresis of the transfer curves and the threshold voltage shifts of SAND-based devices are significantly smaller than those of SiO 2 -based devices. These results demonstrate the improved SAND/ZnO NW interface quality ͑lower interface-trap states and defects͒ in comparison to those fabricated with SiO 2 .

2007

Electronic Noise in Nanostructures: Limitations and Sensing Applications. (December 2006) Jong Un Kim, B.S.; M.S.; Ph.D.; Seoul National University; M.S., Texas AM therefore, electronic noise (i.e., stochastic signals) are generated. As an advanced model, the electrophoretic effect in the SEPTIC sensor is discussed. In the viral sensor, since the combination of the analyte and a specific receptor located at the surface of the silicon nanowire occurs randomly in space and time, a stochastic signal is obtained. A mathematical model for a pH silicon nanowire nanosensor is developed and the size quantization effect in the nanosensor is also discussed. The calculation results are in excellent agreement with the experimental results in the literature.

Microelectronic Engineering, 2013

The properties of Random Telegraph Noise (RTN) in the gate current of nanoscaled Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFET) are discussed. While the gate current RTN capture and emission times depend strongly on temperature and gate voltage, the RTN amplitude, corresponding to single gate oxide leakage path, appears independent of temperature and scaling with the gate current. The RTN amplitude is observed to reach up to tens of percent of gate current. In carrier separation measurements the fluctuations typically appear in one component only. A correlation of drain and gate current fluctuations allows linking the charge and conduction states of a single gate oxide trap. A model for drain current RTN involving a metastable state is extended to include conduction through the single trap and gate current RTN.

IEEE Electron Device Letters, 2000

Abstract Low-frequency noise (LFN) in n-type silicon nanowire MOSFETs (SNWTs) is investigated in this letter. The drain-current spectral density exhibits significant dispersion of up to five orders of magnitude due to the ultrasmall dimensions of SNWTs. The measured ...