A unified flicker noise model which incorporates both the number fluctuation and the correlated surface mobility fluctuation mechanism is discussed. The latter is attributed to the Coulombic scattering effect of the fluctuating oxide charge. The model has a functional form resembling that of the number fluctuation theory, but at certain bias conditions it may reduce to a form compatible with Hooge's empirical expression. The model can unify the noise data reported in the literature, without making any ad hoc assumption on the noise generation mechanism. Specifically, the model can predict the right magnitude and bias dependence of the empirical Hooge parameter. Simulated flicker noise characteristics obtained with a circuit-simulation-oriented flicker noise model based on the new formulation were compared with experimental noise data. Excellent agreement between the calculations and measurement was observed in both the linear and saturation regions for MOS transistors fabricated by different technologies. The work shows that the flicker noise in MOS transistors can be completely explained by the trap charge fluctuation mechanism, which produces mobile carrier number fluctuation and correlated surface mobility fluctuation. >

A unified model for the flicker noise in metal-oxide-semiconductor field-effect transistors

An improved analysis of low frequency trapping noise in a MOS device is proposed. This analysis takes into account the supplementary fluctuations of the mobility induced by those of the interface charge. It enables an adequate description of the gate voltage dependence of the input equivalent gate voltage noise to be obtained in various actual situations. The outputs given by the Hooge mobility fluctuation model are also presented and discussed with respect to those obtained by the carrier number fluctuation model. In particular, the impact of the channel length or channel width, and the model type on the input gate voltage and drain current noise characteristics is studied and compared to typical experimental data. Finally, a procedure for the diagnosis of the low frequency noise sources in a MOS transistor is proposed.

Improved Analysis of Low Frequency Noise in Field‐Effect MOS Transistors

Intrinsic parameter fluctuations introduced by discreteness of charge and matter will play an increasingly important role when semiconductor devices are scaled to decananometer and nanometer dimensions in next-generation integrated circuits and systems. In this paper, we review the analytical and the numerical simulation techniques used to study and predict such intrinsic parameters fluctuations. We consider random discrete dopants, trapped charges, atomic-scale interface roughness, and line edge roughness as sources of intrinsic parameter fluctuations. The presented theoretical approach based on Green's functions is restricted to the case of random discrete charges. The numerical simulation approaches based on the drift diffusion approximation with density gradient quantum corrections covers all of the listed sources of fluctuations. The results show that the intrinsic fluctuations in conventional MOSFETs, and later in double gate architectures, will reach levels that will affect the yield and the functionality of the next generation analog and digital circuits unless appropriate changes to the design are made. The future challenges that have to be addressed in order to improve the accuracy and the predictive power of the intrinsic fluctuation simulations are also discussed.

http://userweb.eng.gla.ac.uk/andrew.brown/papers/IEEE_TED_2003_Review_Paper.pdf

Simulation of intrinsic parameter fluctuations in decananometer and nanometer-scale MOSFETs

We have identified several features of the 1/f noise and radiation response of metal‐oxide‐semiconductor (MOS) devices that are difficult to explain with standard defect models. To address this issue, and in response to ambiguities in the literature, we have developed a revised nomenclature for defects in MOS devices that clearly distinguishes the language used to describe the physical location of defects from that used to describe their electrical response. In this nomenclature, ‘‘oxide traps’’ are simply defects in the SiO2 layer of the MOS structure, and ‘‘interface traps’’ are defects at the Si/SiO2 interface. Nothing is presumed about how either type of defect communicates with the underlying Si. Electrically, ‘‘fixed states’’ are defined as trap levels that do not communicate with the Si on the time scale of the measurements, but ‘‘switching states’’ can exchange charge with the Si. Fixed states presumably are oxide traps in most types of measurements, but switching states can either be interface tr...

Effects of oxide traps, interface traps, and ‘‘border traps’’ on metal‐oxide‐semiconductor devices

This paper presents a quadrature voltage-controlled oscillator (QVCO) based on the coupling of two LC-tank VCOs A simplified theoretical analysis for the oscillation frequency and phase noise displayed by the QVCO in the 1/f/sup 3/ region is developed, and good agreement is found between theory and simulation results A prototype for the QVCO was implemented in a 035-/spl mu/m CMOS process with three standard metal layers The QVCO could be tuned between 164 and 197 GHz, and showed a phase noise of -140 dBc/Hz or less across the tuning range at a 3-MHz offset frequency from the carrier, for a current consumption of 25 mA from a 2-V power supply The equivalent phase error between I and Q signals was at most 025/spl deg/

/pdf/analysis-and-design-of-a-1-8-ghz-cmos-lc-quadrature-vco-3tacbqcgff.pdf

Analysis and design of a 1.8-GHz CMOS LC quadrature VCO

The random telegraph noise exhibited by deep-submicrometer MOSFETs with very small channel area ( >

Random telegraph noise of deep-submicrometer MOSFETs

Discussed is a physics-based MOSFET noise model that can accurately predict the noise characteristics over the linear, saturation, and subthreshold operating regions but which is simple enough to be implemented in any general-purpose circuit simulator. Expressions for the flicker noise power are derived on the basis of a theory that incorporates both the oxide-trap-induced carrier number and correlated surface mobility fluctuation mechanisms. The model is applicable to long-channel, as well as submicron n- and p-channel MOSFETs fabricated by different technologies, and all the model parameters can be easily extracted from routine I-V and noise measurements. >

A physics-based MOSFET noise model for circuit simulators

Random telegraph signal (RTS) measurements have been used to study individual hot-carrier-induced traps in nMOSFETs. It is shown that single filling and emptying can cause 0.1% step noise in channel current. Trap location (3-10 A from interface), time constant ( approximately 10 ms), and energy are found to be quite different from those of prestress (process-induced) traps. The type (acceptor or donor) of the traps can also be identified by RTS measurements; both the process and stress-induced traps with energies near the conduction band edge are found to be of the acceptor type for nMOSFETs and trap levels near the valence band edge are found to be of the donor type for pMOSFETs. Using RTS as a characterization tool, it is found that the stress-induced interface traps are located closer to the interface, resulting in shorter time constants and a stronger influence on the surface mobility than the process-induced traps. >

Hot-electron-induced traps studied through the random telegraph noise

The flicker noise behavior of MOSFETs fabricated by different technologies were characterized. It was found that the technology has very significant effects on the noise characteristics and that all the results can be explained within a unified framework with an oxide trap density distribution. Hot-carrier stressing of n-channel MOSFETs can result in a very large increase of flicker noise, whereas for p-channel MOSFETs the noise is hardly affected. Random telegraph noise is observed in some deep-submicron MOSFETs with very small channel area. A detailed analysis of the telegraph noise suggests that the mobility fluctuation induced by charge trapping plays an important role in the origin of the flicker noise. A novel flicker-noise model incorporating both carrier number and mobility fluctuations is proposed. >

K.K. Hung

Papers

A unified model for the flicker noise in metal-oxide-semiconductor field-effect transistors

Random telegraph noise of deep-submicrometer MOSFETs

A physics-based MOSFET noise model for circuit simulators

Hot-electron-induced traps studied through the random telegraph noise

Flicker noise characteristics of advanced MOS technologies