Analytical Modeling of Flicker Noise in Halo Implanted MOSFETs
20 Apr 2015-IEEE Journal of the Electron Devices Society (Institute of Electrical and Electronics Engineers (IEEE))-Vol. 3, Iss: 4, pp 355-360
TL;DR: An improved analytical model for flicker noise in MOSFETs is presented in this paper, which captures the effect of high-trap density in the halo regions of the devices.
Abstract: An improved analytical model for flicker noise (1/ $f$ noise) in MOSFETs is presented. Current models do not capture the effect of high-trap density in the halo regions of the devices, which leads to significantly different bias dependence of flicker noise across device geometry. The proposed model is the first compact model implementation capturing such effect and show distinct improvements over other existing noise models. The model is compatible with BSIM6, the latest industry standard model for bulk MOSFET, and is validated with measurements from 45-nm low-power CMOS technology node.
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TL;DR: In this article, a BSIM-based compact model for a high-voltage MOSFET is presented, which has been extended to include the overlap capacitance due to the drift region as well as quasi-saturation effect.
Abstract: A BSIM-based compact model for a high-voltage MOSFET is presented. The model uses the BSIM-BULK (formerly BSIM6) model at its core, which has been extended to include the overlap capacitance due to the drift region as well as quasi-saturation effect. The model is symmetric and continuous, is validated with the TCAD simulations and experimental 35- and 90-V LDMOS and 40-V VDMOS transistors, and shows excellent agreement.
23 citations
06 Apr 2020
TL;DR: A new 1/f noise model is presented and the back gate inversion is more physically modeled in the latest BSIM-IMG model for accurate modeling of the FDSOI transistors.
Abstract: FDSOI devices are prominently used in low power circuits and high frequency domains due to their superior RF and analog performance, thanks to back-bias capability and relatively ease of transistor design over FinFETs and planar bulk transistors. BSIM-IMG is the industry standard compact model for simulating FDSOI devices. In this work, we will discuss recent enhancements made in the BSIM-IMG model for accurate modeling of the FDSOI transistors. The back gate inversion is more physically modeled in the latest BSIM-IMG model. We will present a new 1/f noise model, which is validated with the experimental data. Improved output conductance, mobility and gate current models are also discussed. All the enhancements are done in such a way that benchmark RF figure of merit are met.
15 citations
Cites background from "Analytical Modeling of Flicker Nois..."
...However, experimental data from advanced technology nodes has started to show departure from trends suggested by the existing noise model [8], [9]....
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TL;DR: An analytical model, based on the equivalent conductance of the halo device, is developed to understand the anomalous behavior of transconductance in halo implanted MOSFET for linear and saturation regions across both gate and body biases.
Abstract: In this paper, we report anomalous behavior of transconductance ( ${g}_{m}$ ) in halo implanted MOSFET for linear and saturation regions across both gate and body biases. The ${g}_{m}$ characteristics undergo sharp change of slope in saturation which cannot be modeled by conventional compact models. The cause of such behavior is identified and explained using the TCAD simulations of source side halo, drain side halo (DH), both side halos, and uniformly doped transistors. An analytical model, based on the equivalent conductance of the halo device, is developed to understand the ${g}_{m}$ behavior. It is shown that the commonly used approach where only the DH region is considered in saturation, is insufficient to model the atypical ${g}_{m}$ behavior. The effect of oxide thickness ( ${T}_{\text {ox}}$ ) variation on ${g}_{m}$ is also studied, which demonstrates a deviation from the conventional $g_{m}$ behavior for halo implanted devices with thicker ${T}_{\text {ox}}$ . A computationally efficient SPICE model is proposed to model ${g}_{m}$ characteristics which shows excellent matching with the measured data.
15 citations
Cites background or methods from "Analytical Modeling of Flicker Nois..."
...This model is incorporated in the BSIM6 MOS model [7], which is the latest CMC standard compact model of MOS transistor and employs advanced models for various physical effects [14]–[16]....
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...affected from halo implants [4], [16], [21], [22]....
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TL;DR: In this paper, an analytical model that accurately captures anomalous matching characteristics of drain current in a halo-implanted MOSFET across bias, geometry, and temperature is presented.
Abstract: We present an analytical model that accurately captures anomalous matching characteristics of drain current in a halo-implanted MOSFET across bias, geometry, and temperature. It is shown that the variation in drain current in different gate bias regimes results from the random-dopant fluctuations (RDFs) in different spatial regions across the channel of the device with nonuniform channel doping. Such effects cannot be captured by existing compact models. Using the impedance field method to calculate the relative contributions of the RDF in the higher doped halo region and the lower doped channel region, we demonstrate, for the first time, an analytical model that can successfully capture the drain current mismatch from subthreshold to strong inversion. We also report for the first time the unique temperature dependence of matching of the drain current in halo-implanted devices and propose a model to capture this behavior. The model is validated using extensive technology computer-aided design analysis and experimental data and is can be extended to the framework of the industry standard BSIM-BULK (formerly BSIM6) MOS model.
13 citations
Cites background or methods from "Analytical Modeling of Flicker Nois..."
...Using an approach similar to [5], we now use the small-signal analysis...
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...The total normalized mismatch power obtained by adding all σ 2 ID /I 2 D , similar to the PSDs for noise [5], can be expressed by...
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...Recently, we have reported anomalous gm trends and capacitances in halo-implanted devices [5]–[7]....
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TL;DR: In this article, an improved physical equivalent circuit was derived using a transmission line model, by incorporating the high-frequency longitudinal gate electrode and a channel distributed RC network, which was implemented in a BSIM-BULK MOSFET model and validated with dc and RF data, obtained from technology computer aided design device simulations and experimental data.
Abstract: A lumped-circuit nonquasi-static (NQS) model, that is applicable for both large-signal transient simulations and a small-signal ac analysis, is developed in this paper. An improved physical equivalent circuit, capturing NQS effects in the millimeter waveband, is derived using a transmission line model, by incorporating the high-frequency longitudinal gate electrode and a channel distributed RC network. The proposed model is implemented in a BSIM-BULK MOSFET model and validated with dc and RF data, obtained from technology computer-aided design device simulations and experimental data. The proposed model is in very good agreement with the data up to ${50}{f}_{t}$ . The transient currents, for a gate-voltage switching rate of ${5}\times {10}^{{10}}$ V/s, show excellent match with the data. The dc, transient, and ac simulations using the proposed model are much faster than a 10-segmented MOSFET model. This shows that the proposed model is better than other computationally complex compact models, for most RF applications.
10 citations
References
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TL;DR: In this paper, the authors show that 1/ε noise is inversely proportional to the total number of mobile charge carriers in homogeneous samples, and exclude surface effects as the main source of 1/ǫ noise.
1,034 citations
TL;DR: In this paper, a unified flicker noise model which incorporates both the number fluctuation and the correlated surface mobility fluctuation mechanism is discussed, which can unify the noise data reported in the literature, without making any ad hoc assumption on the noise generation mechanism.
Abstract: 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. >
841 citations
"Analytical Modeling of Flicker Nois..." refers background in this paper
...Such behavior cannot be captured by existing noise models based on uniformly doped channel devices [7] (see Fig....
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...There exist popular models which unifies the two approaches [7], [20], [21]....
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TL;DR: In this paper, the use of 1/f noise measurements in n-channel MOSFETs to extract the oxide trap density in space and energy near and above the conduction band edge of silicon is investigated.
Abstract: The use of 1/f noise measurements in n-channel MOSFETs to extract the oxide trap density in space and energy near and above the conduction band edge of silicon is investigated. The conventional carrier number fluctuation model of 1/f noise that attributes 1/f noise to the trapping and detrapping of inversion layer carriers by oxide traps is reviewed. It is shown that oxide band bending in devices with a nonuniform oxide trap distribution leads to a gate voltage dependence in the magnitude and exponent gamma (V/sub gs/) of the 1/f/sup gamma / noise spectrum. An extension of the 1/f noise number fluctuation model that includes both carrier number fluctuations and correlated mobility fluctuations is then studied. Correlated mobility fluctuations are attributed to the coulombic scattering of inversion layer carriers by the fluctuating trapped charge. It is shown that the correlated fluctuation model predicts a gate voltage dependence in the magnitude and exponent gamma of the 1/f/sup gamma / noise spectrum even for a uniform oxide trap distribution. By analyzing the 1/f noise magnitude and exponent data in n-channel MOSFETs having various oxide thicknesses, both models are used to extract the oxide trap density over a wide range of space and energy. >
381 citations
Additional excerpts
...There exist popular models which unifies the two approaches [7], [20], [21]....
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Book•
01 Jan 2006
TL;DR: In this article, the authors present a short history of the EKV most model and its application in IC design, and present an extended version of the model with an extended charge-based model.
Abstract: Foreword. Preface. List of Symbols. 1. Introduction. 1.1 The Importance of Device Modeling for IC Design. 1.2 A Short History of the EKV MOST Model. 1.3 The Book Structure. PART I: THE BASIC LONG-CHANNELINTRINSIC CHARGE-BASED MODEL. 2. Introduction. 2.1 The N-channel Transistor Structure. 2.2 Definition of charges, current, potential and electric fields. 2.3 Transistor symbol and P-channel transistor. 3. The Basic Charge Model. 3.1 Poisson's Equation and Gradual Channel Approximation. 3.2 Surface potential as a Function of Gate Voltage. 3.3 Gate Capacitance. 3.4 Charge Sheet Approximation. 3.5 Density of Mobile Inverted Charge. 3.6 Charge-Potential Linearization. 4. Static Drain Current. 4.1 Drain Current Expression. 4.2 Forward and Reverse Current Components. 4.3 Modes of Operation. 4.4 Model of Drain Current Based on Charge Linearization. 4.5 Fundamental Property: Validity and Application. 4.6 Channel Length Modulation. 5. The Small-Signal Model. 5.1 The Static Small-Signal Model. 5.2 A General Non-Quasi-Static Small-Signal Model. 5.3 The Quasi-Static Dynamic Small-Signal Model. 6. The Noise Model. 6.1 Noise Calculation Methods. 6.2 Low-Frequency Channel Thermal Noise. 6.3 Flicker Noise. 6.4 Appendices. Appendix : The Nyquist and Bode Theorems. Appendix : General Noise Expression. 7. Temperature Effects and Matching. 7.1 Introduction. 7.2 Temperature Effects. PART II: THE EXTENDED CHARGE-BASED MODEL. 8. Non-Ideal Effects Related to the Vertical Dimension. 8.1 Introduction. 8.2 Mobility Reduction Due to the Vertical Field. 8.3 Non-Uniform Vertical Doping. 8.4 Polysilicon Depletion. 8.4.1 Definition of the Effect. 8.5 Band Gap Widening. 8.6 Gate Leakage Current. 9. Short-Channel Effects. 9.1 Velocity Saturation. 9.2 Channel Length Modulation. 9.3 Drain Induced Barrier Lowering. 9.4 Short-Channel Thermal Noise Model. 10. The Extrinsic Model. 10.1 Extrinsic Part of the Device. 10.2 Access Resistances. 10.3 Overlap Regions. 10.4 Source and Drain Junctions. 10.5 Extrinsic Noise Sources. PART III: THE HIGH-FREQUENCY MODEL. 11. Equivalent Circuit at RF. 11.1 RF MOS Transistor Structure and Layout. 11.2 What Changes at RF?. 11.3 Transistor Figures of Merit. 11.4 Equivalent Circuit at RF. 12. The Small-Signal Model at RF. 12.1 The Equivalent Small-Signal Circuit at RF. 12.2 Y-Parameters Analysis. 12.3 The Large-Signal Model at RF. 13. The Noise Model at RF. 13.1 The HF Noise Parameters. 13.2 The High-Frequency Thermal Noise Model. 13.3 HF Noise Parameters of a Common-Source Amplifier. References. Index.
307 citations