用正向栅控二极管的方法对场效应晶体管的参数提取

本文用正向栅控二极管的方法来提取场效应晶体管的栅氧层厚度和体掺杂浓度,尤其是在这两个变量事先都未知的情况下进行提取。首先,用器件物理推导出了以栅氧层厚度、体掺杂浓度为参数的正向栅控二极管峰值电流。然后用ISE-Dessis模拟了不同栅氧层厚度和体衬底掺杂浓度下的产生复合电流峰值的特性,用于参数提取。模拟数据的结果与正向栅控二极管的方法显示出高度的一致性。     

Forward gated-diode method for parameter extraction of MOSFETs

The forward gated-diode method is used to extract the dielectric oxide thickness and body doping concentration of MOSFETs,especially when both of the variables are unknown previously.First,the dielectric oxide thickness and the body doping concentration as a function of forward gated-diode peak recombination-generation (R-G) current are derived from the device physics.Then the peak R-G current characteristics of the MOSFETs with different dielectric oxide thicknesses and body doping concentrations are simulated with ISE-Dessis for parameter extraction.The results from the simulation data demonstrate excellent agreement with those extracted from the forward gated-diode method.     

A simple four-terminal small-signal model of RF MOSFETs and its parameter extraction

After differences between the RF MOSFET and conventional high-frequency transistors, which make the proper modeling of RF MOSFET complicated and difficult, are addressed, a four-terminal small-signal model of an RF MOSFET with a very simple and accurate parameter extraction method is presented. This model includes the intrinsic and extrinsic elements important for RF AC simulation in the strong inversion operation region. Accuracy of the model and extraction method is verified with the measured data and the needs of the intrinsic body node are demonstrated to describe the gate bias dependence of the substrate-signal-coupling effect.     

A small-signal RF model and its parameter extraction for substrateeffects in RF MOSFETs

We propose a physically acceptable small-signal model incorporating substrate effects, in order to eliminate the severe frequency-dependence of the intrinsic drain-source resistance observed from a conventional model of RF Si MOSFETs. This model is based on the substrate network where a parallel RC circuit is connected in series with the drain junction capacitance. It is demonstrated that the substrate effects result in the frequency-dispersion of the effective drain-source resistance and capacitance below 10 GHz. An accurate extraction technique using a simple curve-fit approach is developed to determine substrate parameters directly, and their bulk voltage-dependencies are presented in detail. The validity of this model is partially proved by finding intrinsic parameters exhibiting frequency-independence up to 10 GHz. Better agreement with measured S-parameters is achieved by using the new substrate model rather than the conventional one, verifying the accuracy of the physical model and extraction technique     

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

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.     

Short-channel effect in fully depleted SOI MOSFETs

The short-channel effect in fully depleted silicon-on-insulator MOSFETs has been studied by a two-dimensional analytical model and by computer simulation. The calculated values agree well with the simulation results. It is found that the vertical field through the depleted film strongly influences the lateral field across the source and drain regions. The short-channel effect can be significantly reduced by decreasing the silicon film thickness     

New method for extraction of effective channel length in submicron MOSFETs

A new method for effective channel length extraction in submicron MOSFETS is presented. It is based on measurements of the saturation voltage V/sub DSAT/ in devices with different channel lengths. The method has been tested using submicron double diffused drain (DDD) MOS devices.<>     

Intrinsic parameter fluctuations in decananometer MOSFETs introduced by gate line edge roughness

In this paper, we use statistical three-dimensional (3-D) simulations to study the impact of the gate line edge roughness (LER) on the intrinsic parameters fluctuations in deep decananometer (sub 50 nm) gate MOSFETs. The line edge roughness is introduced using a Fourier synthesis technique based on the power spectrum of a Gaussian autocorrelation function. In carefully designed simulation experiments, we investigate the impact of the rms amplitude /spl Delta/ and the correlation length /spl Lambda/ on the intrinsic parameter fluctuations in well scaled, but simple devices with fixed geometry as well as the channel length and width dependence of the fluctuations at fixed LER parameters. For the first time, we superimpose in the simulations LER and random discrete dopants and investigate their relative contribution to the intrinsic parameter fluctuations in the investigated devices. For particular MOSFET geometries, we were able to identify the regions where each of these two sources of intrinsic parameter fluctuations dominates.     

Evaluation of surface-potential-based bulk-charge compact MOS transistor model

The existing surface-potential-based compact metal-oxide-semiconductor transistor models are based on the 1978 Brews delta-function charge-sheet approximation, which was derived empirically from the 1966 Pao-Sah drift-diffusion double integral formula. This paper provides a device physics-based derivation of a surface-potential-based compact model by analytical approximation of the double and single bulk-charge integrals of the four one-dimensional components of the six-component 1996 Sah two-dimensional formula. In this compact model development, the mobile carrier-space-charge-limited parabolic-drift and linear-diffusion current components are analytically represented by the surface potential without approximation, while the immobile-impurity bulk-space-charge-limited double-integral drift-current and single-integral diffusion-current components are evaluated analytically using three possible surface-potential compact model approximations. This paper calculates the accuracy of these approximate analytical bulk-charge-limited drift and diffusion current components in both the inversion and subthreshold ranges and discusses factors that affect the accuracy in the subthreshold range and near flatband.     

Parameter extraction of accurate and scaleable substrate resistancecomponents in RF MOSFETs

Parameter extraction of the substrate resistance, which becomes important in radio frequency (RF) and mixed signal integrated circuit (IC) design, is discussed based on a simple substrate network of lumped components. By using the measured HF s-parameter data from a set of devices with different geometries, the scaleable parameters for substrate resistances components can be obtained. The simple substrate model with extracted scaleable parameters is accurate for devices with different widths and fingers in a frequency range up to 10 GHz     

Reduction of kink effect in thin-film SOI MOSFETs

Numerical simulation is used to show that potential and electric field distribution within thin, fully depleted SOI devices is quite different from that observed within thicker, partially depleted devices. Reduction of drain electric field and of source potential barrier brings about a dramatic decrease of kink effect     

A self-consistent extraction procedure for source/drain resistance in MOSFETs

A new method to determine source/drain series resistance has been developed for MOSFETs operated in linear region. The source/drain resistance (R_SD) is gate-bias dependent. Channel length reduction (ΔL) is extracted at low gate bias and chosen to be constant. All parameters extracted in this method are assumed to be independent of mask channel length for model simplicity. The method has been applied to devices with mask channel lengths of 0.23, 0.2, and 0.185 μm. The extracted parameters are consistent with the assumptions and have been validated by measured I-V characteristics.     

Body effect in tri- and pi-gate SOI MOSFETs

A simple model based on the representation of capacitive coupling effects between the front- and back-gate and the channels, has been developed for tri-gate and pi-gate SOI MOSFETs. The model has been validated using numerical simulation of the body factor in such devices, as well as by experimental results. The body factor is much smaller than in regular, single-gate silicon-on-insulator devices because of the enhanced coupling between gate and channel and because the lateral gates shield the device from the electrostatic field from the back gate.     

Evaluation of noise parameter extraction methods

The influence of the algorithm used for noise parameter fitting on the accuracy of the microwave noise parameter measurements is investigated. Five different commonly used algorithms are compared by a statistical analysis including instrument accuracy specifications. Some of these algorithms are found to be more efficient in terms of available accuracy and computer time. The best predicted available accuracies reported betwen 4 and 20 GHz for each noise parameter compare well with observed accuracies on noise parameter measurements performed with a dedicated test set on a noise standard made of a passive two-port. The accuracy on minimum noise figure is found to be 0.1 dB maximum     

Reduction of floating substrate effect in thin-film SOI MOSFETs

The presence of a floating substrate in SOI transistors gives rise to a decrease of threshold voltage when drain voltage is increased. When the devices are made in a very thin silicon film, the latter is completely depleted when the device is in the 'on' state, and no part of the film can act as a floating substrate. This brings about a dramatic decrease of the so-called 'kink effect'.     

H型栅结构的亚微米PDSOI MOS器件的跨导双峰效应研究

A bimodal effect of transconductance was observed in narrow channel PDSOI sub-micron H-gate PMOSFETs,which was accompanied with the degeneration of device performance.This paper presents a study of the transconductance bimodal effect based on the manufacturing process and electrical properties of those devices.It is shown that this effect is caused by a diffusion of donor impurities from the NC region of body contact to the PC poly gate at the neck of the H-gate,which would change the work function differences of the polysilicon gate and substrate.This means that the threshold voltage of the device is different in the width direction,which means that there are parasitic transistors paralleled with the main transistor at the neck of the H-gate.The subsequent devices were fabricated with layout optimization,and it is demonstrated that the bimodal transconductance can be eliminated by mask modification with NC implantation more than 0.2 m away from a poly gate.     

Real-time traffic parameter extraction using entropy

A vision-based traffic monitoring system that can perform real-time traffic parameter extraction is proposed. The entropy measurement, which is commonly adopted as an important feature to describe the degree of disorder in thermodynamics, is used as an underlying feature in this work. Based on an entropy measurement, a number of important traffic parameters, such as traffic flow, space mean speed and traffic queue, can be determined in real time. The experimental results clearly show that the proposed system is highly effective.     

On the extraction of the source and drain series resistances of MOSFETs

This article reviews and scrutinizes various proposed methods to extract the individual values of drain and source resistances (R_D and R_S) of MOSFETs, which are important device parameters for modeling and circuit simulation. In general, these methods contain three basic steps: (1) the extraction of the total drain and source resistance (R_D+R_S); (2) the extraction of the difference between the drain and the source resistances (R_D−R_S); and (3) the calculation of R_D and R_S from the knowledge of (R_D+R_S) and (R_D−R_S). These methods are tested and compared in the environments of circuit simulator, device simulation and measurements.     

Static characterization and parameter extraction in MOS transistors

This paper describes the basic concepts for efficient parameter extraction. The focus is on efficiency in parameter extraction and often analytical manipulation of the model equations can be used to increase efficiency. In particular, extraction of the linear region miniset parameters, and how series resistance and effective geometry can be derived from these parameters, will be discussed. Furthermore, extraction of the saturation and subthres-hold region parameters are discussed and the importance of the underlying model is highlighted.     

The effect of gate-voltage-dependent mobility on thermal noise in MOSFETs

It is shown that while the gate-voltage-dependent mobility in MOSFETs has a very large effect upon the (I_ds, V_g) characteristic,, it has only a relatively small effect on the thermal noise parameter α_sat = R_ng_max.