1,721,079 research outputs found
A Frequency- and Space-Domain Series-Expansion Approach for Efficient Numerical Modeling of Semiconductor Devices
No full textAn approach is described that combines frequency-domain Fourier series expansion and space-domain polynomial expansion of the physical quantities inside the semiconductor, for an efficient numerical modelling of high-frequency active devices, based on the solution of the physical transport equations in the semiconductor. The unknowns of the problem are the coefficients of the expansions of the physical quantities in the device channel: electrostatic potential, and electron density, velocity and energy. The frequency- and space-domain expansions drastically reduce the number of time and space sampling points where the equations are computed, greatly reducing the computational burden with respect to classical finite-differences approaches. Moreover, the frequency-domain technique eliminates the need for time-to-frequency transforms for a spectral solution, and allows easy inclusion of frequency-dependent parameters of the semiconductor especially important at very high frequencies (e.g. dielectric constant). Also the coupling with a EM program, for a global modeling simulator, becomes straightforward, due to the reduced interconnection nodes with the physical simulator.
A demonstrator for PC implementing a quasi-2D model with a hydrodynamic formulation with the first three moments of Boltzmann's Transport Equation is given, and its results are compared with a standard finite-difference time-domain approach and with a standard Harmonic Balance formulation
A combined Spatial Polynomial and Spectral-Balance Frequency-Domain Approach for Efficient Physic-based Analysis of Sub-micron Devices
No full textNonlinear Microwave Circuit Design
No full textNonlinear microwave circuits is a field still open to investigation; however, many basic
concepts and design guidelines are already well established. Many researchers and design
engineers have contributed in the past decades to the development of a solid knowledge
that forms the basis of the current powerful capabilities of microwave engineers.
This book is composed of two main parts. In the first part, some fundamental tools
are described: nonlinear circuit analysis, nonlinear measurement, and nonlinear model-
ing techniques. In the second part, basic structure and design guidelines are described
for some basic blocks in microwave systems, that is, power amplifiers, oscillators, fre-
quency multipliers and dividers, and mixers. Stability in nonlinear operating conditions
is also addressed.
A short description of fundamental techniques is needed because of the inherent
differences between linear and nonlinear systems and because of the greater familiarity
of the microwave engineer with the linear tools and concepts. Therefore, an introduction
to some general methods and rules proves useful for a better understanding of the basic
behaviour of nonlinear circuits. The description of design guidelines, on the other hand,
covers some well-established approaches, allowing the microwave engineer to understand
the basic methodology required to perform an effective design.
The book mainly focuses on general concepts and methods, rather than on practical
techniques and specific applications. To this aim, simple examples are given throughout
the book and simplified models and methods are used whenever possible. The expected
result is a better comprehension of basic concepts and of general approaches rather than
a fast track to immediate design capability
Global Modeling Analysis of HEMTs by the Spectral Balance Technique
No full textA global physical/electromagnetic HEMT simulation approach, entirely in the frequency domain, is here described for microwave CAD applications. The frequency-domain Spectral Balance technique for the solution of steady-state nonlinear differential equations is applied to the moments of Boltzmann's Transport Equation for the analysis of the intrinsic, active part of the device, yielding a very simple formulation. A numerical electromagnetic solver in the frequency domain is used for the analysis of the extrinsic, passive embedding and access structure. The two analyses are coupled, and give a self-consistent, global description of the device. The frequency-domain formulation allows easy inclusion of frequency-dependent parameters of the semiconductor, and a natural extension to multitone analysis, without the need for cumbersome time-frequency transformations. The thechnique is applied to a Quasi-2-Dimensional (Q-2D) hydrodynamic modeling of the active device for simplicity, but is suitable for more comprehensive approaches as well. DC and small-signal microwave results up to 40 GHz are obtained for a 0.3-μm gate-length AlGaAs–InGaAs–GaAs pHEMT transistor, and compared to experimental data
Quasi-2D Frequency-Domain Physical Modeling of MOSFETs by the Spectral Balance Technique
No full text
Physical/Electromagnetic Analysis of Multifinger MOSFETs with SB-SP Combined Methods
No full textIn this paper, the frequency-domain Spectral Balance technique, which has been demonstrated to be a viable alternative to the mixed-domain Harmonic Balance technique is combined to the space-domain polynomial expansion of the physical quantities inside the semiconductor for the solution of steady-state nonlinear differential equations and applied to the physical analysis of multifinger MOSFET devices in linear and nonlinear regime and coupled to a commercial electromagnetic solver. This method allows a really fast CAD analysis both in DC and RF periodic regime especially when global modeling is required. A quasi-2D hydrodynamic formulation is given for a 0.35μm gate length with 10μm periphery three finger MOSFET; results are compared to those of a standard physical time-domain, a Harmonic Balance and Spectral Balance for time comparison. Moreover S-parameter comparisons with a commercial CAD tools with a compact model for circuit analysis are also given
Harmonic solution of semiconductor transport equations for microwave and millimetre-wave device modeling
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