A Study on SPICE Modeling of Non-Resonant Plasmonic Terahertz Detector

Department Of Electrical EngineeringThe terahertz (sub-millimeter wave) is the frequency resource, ranging from 100 GHz ~ 10 THz band, located in the middle region of the infrared and millimeter waves in the electromagnetic spectrum. Terahertz waves has unique physical characteristics, which is transparency of radio waves and straightness of light waves, simultaneously. The terahertz wave is applied to the basic science, such as device, spectroscopy, and imaging technology. And also adjust in the applied science, such as biomedical engineering, security, environment, information and communication. Which importance already verified. In the new shape of future market is expected to be formed broadly. For this application, operating in the THz frequency detecting device essential. Recently, Current elements operating in terahertz are present, such as compound semiconductor (???-???HBT, HEMT). But, there are disadvantage to use as a high price. Therefore, research have been made of silicon based THz detector in many research groups. Silicon-based nano-technology utilizes a plasma wave transistor technology. Which is using the space-time change of the channel charge density. That causes plasma wave oscillation in the MOSFET (Metal oxide semiconductor field effect transistor) channel and this effect available MOSET operating terahertz regime beyond MOSFET cut-off frequency. So, PWT (plasma wave transistor) is available terahertz detection and oscillation. For integrated possible post processing circuit development in these of terahertz applications system, silicon based PWT compact model is essential thing. For this compact model for spice simulation beyond cut-off frequency, we consider charge time variance model which is NQS (non-quasi-static) model, not quasi-static model. For NQS model two kinds of model exist, first is RC ladder model. That is seral connect MOSFET get rid of parasitic elements. And these complex circuit making the equivalent circuit model, it called New Elmore model. For post processing circuit simulation, fast simulation speed is essential, RC ladder model has a disadvantage (for simulating each segment). In this thesis we using New Elmore model based on Non-resonant plasmonic THz detector modeling, And verified physical validity of our NQS model using the our TCAD model based on Quasi-plasma 2DEG. And we propose fast and accurate compact modelingope

A Study on SPICE Modeling of Non-Resonant Plasmonic Terahertz Detector

Department Of Electrical EngineeringThe terahertz (sub-millimeter wave) is the frequency resource, ranging from 100 GHz ~ 10 THz band, located in the middle region of the infrared and millimeter waves in the electromagnetic spectrum. Terahertz waves has unique physical characteristics, which is transparency of radio waves and straightness of light waves, simultaneously. The terahertz wave is applied to the basic science, such as device, spectroscopy, and imaging technology. And also adjust in the applied science, such as biomedical engineering, security, environment, information and communication. Which importance already verified. In the new shape of future market is expected to be formed broadly. For this application, operating in the THz frequency detecting device essential. Recently, Current elements operating in terahertz are present, such as compound semiconductor (???-???HBT, HEMT). But, there are disadvantage to use as a high price. Therefore, research have been made of silicon based THz detector in many research groups. Silicon-based nano-technology utilizes a plasma wave transistor technology. Which is using the space-time change of the channel charge density. That causes plasma wave oscillation in the MOSFET (Metal oxide semiconductor field effect transistor) channel and this effect available MOSET operating terahertz regime beyond MOSFET cut-off frequency. So, PWT (plasma wave transistor) is available terahertz detection and oscillation. For integrated possible post processing circuit development in these of terahertz applications system, silicon based PWT compact model is essential thing. For this compact model for spice simulation beyond cut-off frequency, we consider charge time variance model which is NQS (non-quasi-static) model, not quasi-static model. For NQS model two kinds of model exist, first is RC ladder model. That is seral connect MOSFET get rid of parasitic elements. And these complex circuit making the equivalent circuit model, it called New Elmore model. For post processing circuit simulation, fast simulation speed is essential, RC ladder model has a disadvantage (for simulating each segment). In this thesis we using New Elmore model based on Non-resonant plasmonic THz detector modeling, And verified physical validity of our NQS model using the our TCAD model based on Quasi-plasma 2DEG. And we propose fast and accurate compact modelingope

An ultra-compact virtual source FET model for deeply-scaled devices: Parameter extraction and validation for standard cell libraries and digital circuits

In this paper, we present the first validation of the virtual source (VS) charge-based compact model for standard cell libraries and large-scale digital circuits. With only a modest number of physically meaningful parameters, the VS model accounts for the main short-channel effects in nanometer technologies. Using a novel DC and transient parameter extraction methodology, the model is verified with simulated data from a well-characterized, industrial 40-nm bulk silicon model. The VS model is used to fully characterize a standard cell library with timing comparisons showing less than 2.7% error with respect to the industrial design kit. Furthermore, a 1001-stage inverter chain and a 32-bit ripple-carry adder are employed as test cases in a vendor CAD environment to validate the use of the VS model for large-scale digital circuit applications. Parametric Vdd sweeps show that the VS model is also ready for usage in low-power design methodologies. Finally, runtime comparisons have shown that the use of the VS model results in a speedup of about 7.6×.Masdar Institute of Science and Technology (Massachusetts Institute of Technology Cooperative Agreement

Semiconductor Device Modeling and Simulation for Electronic Circuit Design

This chapter covers different methods of semiconductor device modeling for electronic circuit simulation. It presents a discussion on physics-based analytical modeling approach to predict device operation at specific conditions such as applied bias (e.g., voltages and currents); environment (e.g., temperature, noise); and physical characteristics (e.g., geometry, doping levels). However, formulation of device model involves trade-off between accuracy and computational speed and for most practical operation such as for SPICE-based circuit simulator, empirical modeling approach is often preferred. Thus, this chapter also covers empirical modeling approaches to predict device operation by implementing mathematically fitted equations. In addition, it includes numerical device modeling approaches, which involve numerical device simulation using different types of commercial computer-based tools. Numerical models are used as virtual environment for device optimization under different conditions and the results can be used to validate the simulation models for other operating conditions

Modeling and Analysis of Plasmonic Terahertz Wave Detector Based on Field Effect Transistor

Department of Electrical EngineeringI propose accurate analysis and novel model of the nonresonant plasmonic terahertz (THz) wave detector based on the silicon (Si) field effect transistor (FET) with a technology computer-aided design (TCAD) platform and SPICE simulation. By introducing a quasi-plasma two-dimensional electron gas (2DEG) in the channel of the FET, the physical behavior of the plasma wave has been modeled with the TCAD platform. For accurate analysis of the modulation and propagation of the channel electron density as the plasma wave, I have characterized the quasi-plasma 2DEG model with two key parameters, such as quasi-plasma 2DEG length (lQP) and density (NQP). The lQP and NQP is defined exactly as extracting the average point of the electron density by using the normalization method. Through the quasi-plasma 2DEG modeling, I investigate the performance enhancement of the plasmonic terahertz wave detector based on Si FET according to scaling down the gate oxide thickness (tox), which is a significant parameter of FET-based plasmonic terahertz detector for the channel electron density modulation. By scaling down tox, the responsivity (Rv) and noise equivalent power (NEP), which are the important performance metrics of the THz wave detector, have been enhanced. In addition, I report the new NQS compact model for MOSFET-based THz wave detector using SPICE simulation. Because the FETs are intensively considered for THz detector due to their performance and applicability, it is essential to describe the physical behaviors of FET in the THz regime with non-quasi-static (NQS) analysis. However, most of the NQS MOSFET models (e.g., Elmore model) have the complexity of the formulation and fail to describe the device physics for the accurate analysis of fast switching and high-frequency operation. In this work, I have proposed novel NQS compact model of MOSFET, which is applicable for transient simulation of the plasmonic THz detectors. The new SPICE NQS model has been verified by comparing with TCAD device simulation as reference of the complete numerical NQS simulation. For simulation of MOSFET-based plasmonic THz detector with SPICE, I demonstrate the model validity by extracting the photoresponse simulation as the function of the gate voltage at 0.2 THz with the peak point in the sub-threshold region. The proposed novel methodologies will provide the advanced physical analysis and efficient structural design for developing the nonresonant plasmonic terahertz detectors operating in THz regime.ope

Resonance mode power supplies with power factor correction

There is an increasing need for AC-DC converters to draw a pure sinusoidal current at near unity power factor from the AC mains. Most conventional power factor correcting systems employ PWM techniques to overcome the poor power factor being presented to the mains. However, the need for smaller and lighter power processing equipment has motivated the use of higher internal conversion frequencies in the past. In this context, resonant converters are becoming a viable alternative to the conventional PWM controlled power supplies. The thesis presents the implementation of active power factor correction in power supplies, using resonance mode techniques. It reviews the PWM power factor correction circuit topologies previously used. The possibility of converting these PWM topologies to resonant mode versions is discussed with a critical assessment as to the suitability of the semiconductor switching devices available today for deployment in these resonant mode supplies. The thesis also provides an overview of the methods used to model active semiconductor devices. The computer modelling is done using the PSpice microcomputer simulation program. The modifications that are needed to the built in MOSFET model in PSpice, when modeling high frequency circuits is discussed. A new two transistor model which replicates the action of a OTO thyristor is also presented. The new model enables the designer to estimate the device parameters with ease by adopting a short calculation and graphical design procedure, based on the manufacturer's data sheets. The need for a converter with a high efficiency, larger power/weight ratio, high input power factor with reduced line current distortion and reduced cost has led to the development of a new resonant mode converter topology, for power processing. The converter presents a near resistive load to the mains thus ensuring a high input power factor, while providing a stabilised de voltage at the output with a small lOOHz ripple. The supply is therefore ideal for preregulation applications. A description of the modes of operation and the analysis of the power circuit are included in the thesis. The possibility of using the converter for low output voltage applications is also discussed. The design of a 300W, 80kHz prototype model of this circuit is presented in the thesis. The design of the isolation transformer and other magnetic components are described in detail. The selection of circuit components and the design and implementation of the variable frequency control loop are also discussed. An evaluation of the experimental and computer simulated results obtained from the prototype model are included in the presentation. The thesis further presents a zero-current switching quasi-resonant flyback circuit topology with power factor correction. The reasons for using this topology for off-line power conversion applications are discussed. The use of a cascoded combination of a bipolar power transistor and two power MOSFETs i~ the configuration has enabled the circuit to process moderate levels of power while simultaneously switching at high frequencies. This fulfils the fundamental precondition for miniaturisation. It also provides a well regulated DC output voltage with a very small ripple while maintaining a high input power factor. The circuit is therefore ideal for use in mobile applications. A preliminary design of the above circuit, its analysis using PSpice, the design of the control circuit, current limiting and overcurrent protection circuitry and the implementation of closed-loop control are all included in the thesis. The experimental results obtained from a bread board model is also presented with an evaluation of the circuit performance. The power factor correction circuit is finally installed in this supply and the overall converter performance is assessed

An integrated simulation for VLSI design environment

Call number: LD2668 .R4 EECE 1989 C53Master of ScienceElectrical and Computer Engineerin

Surface Potential-Based Polycrystalline-Silicon Thin-Film Transistors Compact Model by Nonequilibrium Approach

We propose a surface potential-based polycrystalline silicon thin-film transistors (poly-Si TFTs) compact model considering a nonequilibrium state. A drain current model considers grain boundary (GB) trap-related physical phenomena: composite mobility of GB and intragrain, GB bias-induced mobility modulation, transient behavior because of carrier capture and emission at GBs, pinch off voltage lowering, and GB trap-assisted leakage current. Besides, photoinduced current behavior is also considered by introducing quasi-Fermi potential. A capacitance model is derived from physically partitioned terminal charges and coupled to the drain current. This compact model allows us to accurately simulate static characteristics of various types of poly-Si TFTs, including temperature and luminance dependence. Furthermore, it succeeded to simulate frequency dependence of circuit performance derived from the trap-related transient behavior, which was verified by evaluating delay time in a 21-stage inverter chain