Comprehensive Analytical Models of Random Variations in Subthreshold MOSFET’s High-Frequency Performances

Subthreshold MOSFET has been adopted in many low power VHF circuits/systems in which their performances are mainly determined by three major high-frequency characteristics of intrinsic subthreshold MOSFET, i.e., gate capacitance, transition frequency, and maximum frequency of oscillation. Unfortunately, the physical level imperfections and variations in manufacturing process of MOSFET cause random variations in MOSFET’s electrical characteristics including the aforesaid high-frequency ones which in turn cause the undesired variations in those subthreshold MOSFET-based VHF circuits/systems. As a result, the statistical/variability aware analysis and designing strategies must be adopted for handling these variations where the comprehensive analytical models of variations in those major high-frequency characteristics of subthreshold MOSFET have been found to be beneficial. Therefore, these comprehensive analytical models have been reviewed in this chapter where interesting related issues have also been discussed. Moreover, an improved model of variation in maximum frequency of oscillation has also been proposed

Analysis and comprehensive analytical modeling of statistical variations in subthreshold MOSFET's high frequency characteristics

In this research, the analysis of statistical variations in subthreshold MOSFET's high frequency characteristics defined in terms of gate capacitance and transition frequency, have been shown and the resulting comprehensive analytical models of such variations in terms of their variances have been proposed. Major imperfection in the physical level properties including random dopant fluctuation and effects of variations in MOSFET's manufacturing process, have been taken into account in the proposed analysis and modeling. The up to dated comprehensive analytical model of statistical variation in MOSFET's parameter has been used as the basis of analysis and modeling. The resulting models have been found to be both analytic and comprehensive as they are the precise mathematical expressions in terms of physical level variables of MOSFET. Furthermore, they have been verified at the nanometer level by using 65~nm level BSIM4 based benchmarks and have been found to be very accurate with smaller than 5 % average percentages of errors. Hence, the performed analysis gives the resulting models which have been found to be the potential mathematical tool for the statistical and variability aware analysis and design of subthreshold MOSFET based VHF circuits, systems and applications

Novel expressions for time domain responses of fractance device

In this research, many novel expressions for time domain responses of fractance device to various often cited inputs have been proposed. Unlike the previous ones, our expressions have been derived based on the Caputo fractional derivative by also concerning the dimensional consistency with the integer order device based responses and the different between two types of fractance device i.e. fractional order inductor and fractional order capacitor. These previous expressions have been derived based on the Riemann-Liouvielle fractional derivative which has certain features that leads to contradictions and additional modeling difficulties unlike the Caputo fractional derivative. Our new expressions are applicable to both fractional order inductor and capacitor with arbitrary order. They are also applicable to any subject which its electrical characteristic can be modeled based on the fractance device. With our expressions and numerical simulations, the time domain behavioral analysis of both fractance device and such subject can be directly performed without requiring any time to frequency domain conversion and its inverse as already presented in this work. Therefore our work has been found to be beneficial to various fractance device related disciplines e.g. biomedical engineering, control system, electronic circuit and electrical engineering etc

Analysis of Memreactance with Fractional Kinetics

In this work, the analysis of the memreactance, i.e., meminductor and memcapacitor, with fractional-order kinetics has been proposed. The meminductances, memcapacitances, and related parameters due to both DC and periodic input waveforms have been derived. The behavioral analysis has been thoroughly performed with the aid of numerical simulation. The effects of fractional-order kinetics have been explored where both linear and nonlinear dopant drift scenarios have been considered. Moreover, the emulation of memreactance with fractional-order kinetics by using the memristor and the effect of the fractional-order kinetics on the memreactance-based circuits have also been mentioned along with the extension of our results to the fractional-order memreactance

Novel Complete Probabilistic Models of Random Variation in High Frequency Performance of Nanoscale MOSFET

The novel probabilistic models of the random variations in nanoscale MOSFET's high frequency performance defined in terms of gate capacitance and transition frequency have been proposed. As the transition frequency variation has also been considered, the proposed models are considered as complete unlike the previous one which take only the gate capacitance variation into account. The proposed models have been found to be both analytic and physical level oriented as they are the precise mathematical expressions in terms of physical parameters. Since the up-to-date model of variation in MOSFET's characteristic induced by physical level fluctuation has been used, part of the proposed models for gate capacitance is more accurate and physical level oriented than its predecessor. The proposed models have been verified based on the 65 nm CMOS technology by using the Monte-Carlo SPICE simulations of benchmark circuits and Kolmogorov-Smirnov tests as highly accurate since they fit the Monte-Carlo-based analysis results with 99% confidence. Hence, these novel models have been found to be versatile for the statistical/variability aware analysis/design of nanoscale MOSFET-based analog/mixed signal circuits and systems

The modified alpha power law based model of statistical fluctuation in nanometer FGMOSFET

The modified alpha power law based model of statistical fluctuation in drain current of an unconventional Metal Oxide Semiconductor Field Effect Transistor namely Floating-Gate Metal Oxide Semiconductor Field Effect Transistor (FGMOSFET) has been proposed where the nanometer FGMOSET have been focused. Unlike the previous works, the fluctuation in drain current has been expressed in a per-unit basis which is able to show the true criticality of such fluctuation, and those previously assumed approximations on FGMOSFET’s parameters have not been adopted. The process induced device level statistical fluctuations and the related correlations have been taken into account. Nonlinearity of voltage at the floating gate and dependency on voltage at the drain terminal of the coupling factors have also been concerned. The proposed model can accurately fit the 65 nm 4th generation Berkeley Short-channel IGFET Model (BSIM4) based reference obtained from the Monte-Carlo simulation by using FGMOSFET Simulation Program with Integrated Circuit Emphasis based simulation technique. If desired, it can fit those references based on smaller technologies by using the optimally extracted drain current parameters of those technologies. From our model, the statistical fluctuation reducing strategies of nanometer FGMOSFET can be obtained. Moreover, the application of the model to the candidate nanometer FGMOSFET based circuit has also been shown

Analytical Model of Random Variation in Drain Current of FGMOSFET

The analytical model of random variation in drain current of the Floating Gate MOSFET (FGMOSFET) has been proposed in this research. The model is composed of two parts for triode and saturation region of operation where the process induced device level random variations of each region and their statistical correlations have been taken into account. The nonlinearity of floating gate voltage and dependency on drain voltage of the coupling factors of FGMOSFET have also been considered. The model has been found to be very accurate since it can accurately fit the SPICE BSIM3v3 based reference obtained by using Monte-Carlo SPICE simulation and FGMOSFET simulation technique with SPICE. It can fit the BSIM4 based reference if desired by using the optimally extracted parameters. By using the proposed model, the variability analysis of FGMOSFET and the analytical modeling of the variation in the circuit level parameter of any FGMOSFET based circuit can be performed. So, this model has been found to be an efficient tool for the variability aware analysis and design of FGMOSFET based circuit

On the fractional domain generalization of memristive parametric oscillators

In this research, we generalize a family of electronic parametric oscillators in the fractional domain by using a state of the art circuit element namely fractional memristor. Such family of parametric oscillators is the memristor based Wien family which is an extension of the normal Wien family. Noted that such normal Wien family is one family of the simplest second-order nonparametric oscillators. We derive the equations of the range of oscillating frequency, sustained oscillating frequency, sustained oscillating condition and the output voltage by using our mathematical model of the fractional memristor as the basis. With the obtained results and numerical simulations, the effects of the fractional memristor to the generalized parametric oscillators have been studied where the validation has been performed based on the SPICE HP memristor model. We have found that those oscillators with the fractional memristor of order greater than unity are more preferable

Gaussian Mixture Density based Analytical Model of Noise Induced Variation in Key Parameter of Electronically Tunable Device

In this research, the Gaussian mixture density based analytical model of variation in key parameter of electronically tunable device has been originally proposed. The proposed model is applicable to any electronically tunable device with its tuning variable has been affected by any kind of noise with arbitrary parameters. It has been found from the verification by using different electronically tunable device based empirical distributions and the Kolmogorov-Smirnov tests that this novel model is very accurate. So, it has been found to be a convenient mathematical tool for the analysis and design of various electronically tunable device based circuits