Overview of the impact of downscaling technology on 1∕f noise in p-MOSFETs to 90 nm (original) (raw)
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International Journal of Electronics, 2001
Silicon founders give in their MOS transistor card models some low-frequency noise parameters for SPICE-based circuit simulators corresponding to pure 1=f a or¯icker noise, with a very close to unity. MOS transistors used in analogue circuit applications are usually devices with large channel length and width. In low-noise applications, methods such as correlated double sampling are used to suppress the low frequency noise generated by them. Nevertheless, the transistors presently are submicrometre devices exhibiting very diOE erent low-frequency noise behaviour. In this paper, experimental low-frequency noise results obtained at room temperature on NMOS and PMOS transistors fabricated using a 0.7 mm process are presented. Both large and small devices on the same process are considered. All regions of operation of transistors are considered. We show that the low-frequency noise behaviour of small area MOSFETs is very diOE erent from that of large area devices and that the spectrum is the summation of Lorentzian spectra generated by the switching of individual active traps.
1/f noise measurements in n-channel MOSFETs processed in 0.25 μm technology
Solid-State Electronics, 2002
Low frequency noise has been studied from the weak to strong inversion regime in n-channel MOS transistors. The 1=f current noise power spectrum density S ID is measured as a function of the drain current and gate voltage with the gate length as a parameter. Analysis of the noise characteristics shows that the channel noise agrees with the mobility fluctuation model and can be predicted in the linear and saturation region using the a H parameter only. Finally, the three parameters NOIA, NOIB and NOIC used in the BSIM3v3 noise model are extracted. Some discrepancies of the noise simulation with the experimental data are observed. Ó
1/f Noise in CMOS transistors for analog applications from subthreshold to saturation
Solid-State Electronics, 1998
ÐDetailed noise measurements of the 1/f noise in p-and n-mos transistors for analog applications are reported under various bias conditions ranging from subthreshold to saturation. The CMOS transistors under study have a relatively large area, exhibit long channel behavior and are fabricated in a commercial``low noise process'', as prescribed for analog applications. A clear methodology and useful models for the power spectral densities of the gate voltage and drain current are presented and are based on recent studies in sub-micron transistors that have established the physical origin of 1/ f noise in MOS transistors. In saturation, it is found that it is advisable to limit the bias voltages to values that are experimentally determined from the transconductance characteristics and correspond to a nearly constant channel mobility. The experimentally observed reduction in channel mobility indicates the existence of strong ®elds that induce additional oxide charging and hence an increase in the eective density of oxide traps and the noise. In the bias voltages where channel mobility is nearly constant, the measured input-referred noise power is practically constant. Below threshold voltage, a reduction is observed in the input-referred noise as gate voltage is decreased, corresponding to the prediction of the model and due to the exponential reduction of the inversion capacitance with gate voltage. This behavior is observed for both n-mos and p-mos transistors.
An improved physics-based 1/ f noise model for deep sub-micron MOSFETs
Solid-state Electronics, 2001
1/f noise has been investigated on the drain to source voltage of deep sub-micron p-channel MOSFETs, with 5 μm channel width and 0.32–1.2 μm varying lengths. The MOSFETs were fabricated using 0.18 μm medium doped drain technology. The measurements were performed in strong inversion and linear operation region at room temperature. Noise parameters for BSIM3 simulation were extracted from the
1/f noise in advanced CMOS transistors
IEEE Instrumentation & Measurement Magazine, 2000
C omplementary metal-oxide-semiconductor (CMOS) technology is dominant in the microelectronics industry for a wide range of applications, including analog, digital, RF, and sensor systems. The advantages of silicon CMOS technology compared to bipolar technology as well as transistors in other semiconductors is well-established. CMOS technology scaling has been a main drive for continuous progress in the silicon based semiconductor industry over the past two decades . The continuous downscaling of CMOS technologies towards nano feature size has increased the performance of integrated circuits considerably. However, one important limitation of MOSFET downscaling is an increase of 1/f noise (often referred to as low-frequency noise), since the 1/f noise increases as the reciprocal of the device area [2], . Furthermore, the development of nano-sized CMOS technologies has led to the observation of random telegraph signals (RTS) yielding large low frequency current fluctuations. Excessive low-frequency noise introduces serious limitations on the functionality of analog and digital circuits since it deteriorates the noise figure of operational amplifiers and A/D and D/A converters. Lowfrequency noise diminishes the signal-to-noise-ratio (SNR) of CMOS sensors, such as IR or CMOS image sensors [5] .
Improved analysis and modeling of low-frequency noise in nanoscale MOSFETs
Solid-State Electronics, 2012
Extensive investigation of the low-frequency noise in n-channel and p-channel MOSFETs, with high-k gate stack and channel length varying from 1.8 lm down to 26.4 nm, has been carried out. The results demonstrate that the carrier number fluctuation with correlated mobility fluctuations describes accurately and continuously the 1/f noise for all operation regions, i.e. from weak to strong inversion and from linear to saturation. It has been found that the product of the Coulomb scattering coefficient and the effective carrier mobility a sc l eff is constant over a wide range of the drain current due to the interplay of the Coulomb scattering coefficient a sc and the effective carrier mobility l eff variations. In addition, a non-linear increase in the square root of the input gate voltage noise with the gate voltage overdrive was observed explained by the surface roughness scattering. The overall results lead to an analytical expression for the 1/f noise model, enabling to predict the noise level of a transistor with any channel dimensions using its transfer characteristic. This finding makes the noise model suitable for circuit simulation tools.
Low frequency noise of p and n type MOSFETs were investigated. Flicker noise was found dominating in the spectra of MOSFETs low frequency fluctuations. Simulations were performed using both models associated with mobility fluctuations and trapping of current. Good fit of the simulated to the measured noise data enabled an extraction of the effective density of the interface states, the spectral density of the flat band voltage fluctuations and Hooge parameter α α α αH H H H. For n type MOSFETs grown on the same wafer the flicker noise was found to be one order of magnitude higher than that for the p type devices.
Low-Frequency Noise in MOSFETs
—As soon as inherent noise of MOSFET becomes an issue in the design of ICs, accurate physics-based models are necessary. The present paper reviews the different noise sources responsible for MOSFET drain current fluctuation. The long-running question of the physical origin of 1/f noise is briefly addressed. Special attention is paid to the Random Telegraph Noise (RTN) since it gets as significant as statistical variability in deeply-scaled CMOS technologies. Due to the extreme complexity of the underlying physical mechanism, which is capture and emission of carrier by an oxide defect, we adopt a phenomenological approach. A stochastic model is firstly derived. Then, the fundamental physical parameters are discussed based on the simple Shockley-Read-Hall theory and the charge sheet approximation.
Solid-State Electronics, 2005
The drain current activation energy dependence on the gate voltage is first evaluated from temperature measurements in both low temperature (6600°C) polysilicon thin film transistors and in crystalline silicon N-MOSFETs, operating from sub-threshold to above-threshold regions. The noise behaviour of these transistors is then described with a low frequency noise model based on the Meyer-Neldel drain current expression. This model is built on carrier fluctuations at the gate oxide/active layer interface and the corresponding defect density is then deduced. It suggests that these defects close to the interface, causing detrapping/trapping processes of carriers and fluctuations of the flat-band voltage, are mainly responsible for the low frequency noise in the two operating modes. Noise measurements on different N-MOS transistors are confronted to result from the presented model.
Evaluation of Low-Frequency Noise in MOSFETs Used as a Key Component in Semiconductor Memory Devices
Electronics
Methods for evaluating low-frequency noise, such as 1/f noise and random telegraph noise, and evaluation results are described. Variability and fluctuation are critical in miniaturized semiconductor devices because signal voltage must be reduced in such devices. Especially, the signal voltage in multi-bit memories must be small. One of the most serious issues in metal-oxide-semiconductor field-effect-transistors (MOSFETs) is low-frequency noise, which occurs when the signal current flows at the interface of different materials, such as SiO2/Si. Variability of low-frequency noise increases with MOSFET shrinkage. To assess the effect of this noise on MOSFETs, we must first understand their characteristics statistically, and then, sufficient samples must be accurately evaluated in a short period. This study compares statistical evaluation methods of low-frequency noise to the trend of conventional evaluation methods, and this study’s findings are presented.