Simulation of Transport in Nanodevices


Book Description

Linear current-voltage pattern, has been and continues to be the basis for characterizing, evaluating performance, and designing integrated circuits, but is shown not to hold its supremacy as channel lengths are being scaled down. In a nanoscale circuit with reduced dimensionality in one or more of the three Cartesian directions, quantum effects transform the carrier statistics. In the high electric field, the collision free ballistic transform is predicted, while in low electric field the transport remains predominantly scattering-limited. In a micro/nano-circuit, even a low logic voltage of 1 V is above the critical voltage triggering nonohmic behavior that results in ballistic current saturation. A quantum emission may lower this ballistic velocity.




The Wigner Monte Carlo Method for Nanoelectronic Devices


Book Description

The emergence of nanoelectronics has led us to renew the concepts of transport theory used in semiconductor device physics and the engineering community. It has become crucial to question the traditional semi-classical view of charge carrier transport and to adequately take into account the wave-like nature of electrons by considering not only their coherent evolution but also the out-of-equilibrium states and the scattering effects. This book gives an overview of the quantum transport approaches for nanodevices and focuses on the Wigner formalism. It details the implementation of a particle-based Monte Carlo solution of the Wigner transport equation and how the technique is applied to typical devices exhibiting quantum phenomena, such as the resonant tunnelling diode, the ultra-short silicon MOSFET and the carbon nanotube transistor. In the final part, decoherence theory is used to explain the emergence of the semi-classical transport in nanodevices.




The Non-Equilibrium Green's Function Method for Nanoscale Device Simulation


Book Description

For modeling the transport of carriers in nanoscale devices, a Green-function formalism is the most accurate approach. Due to the complexity of the formalism, one should have a deep understanding of the underlying principles and use smart approximations and numerical methods for solving the kinetic equations at a reasonable computational time. In this book the required concepts from quantum and statistical mechanics and numerical methods for calculating Green functions are presented. The Green function is studied in detail for systems both under equilibrium and under nonequilibrium conditions. Because the formalism enables rigorous modeling of different scattering mechanisms in terms of self-energies, but an exact evaluation of self-energies for realistic systems is not possible, their approximation and inclusion in the quantum kinetic equations of the Green functions are elaborated. All the elements of the kinetic equations, which are the device Hamiltonian, contact self-energies and scattering self-energies, are examined and efficient methods for their evaluation are explained. Finally, the application of these methods to study novel electronic devices such as nanotubes, graphene, Si-nanowires and low-dimensional thermoelectric devices and photodetectors are discussed.




Advanced Device Modeling and Simulation


Book Description

Microelectronics is one of the most rapidly changing scientific fields today. The tendency to shrink devices as far as possible results in extremely small devices which can no longer be described using simple analytical models. This book covers various aspects of advanced device modeling and simulation. As such it presents extensive reviews and original research by outstanding scientists. The bulk of the book is concerned with the theory of classical and quantum-mechanical transport modeling, based on macroscopic, spherical harmonics and Monte Carlo methods.




Transport of Information-Carriers in Semiconductors and Nanodevices


Book Description

Rapid developments in technology have led to enhanced electronic systems and applications. When utilized correctly, these can have significant impacts on communication and computer systems. Transport of Information-Carriers in Semiconductors and Nanodevices is an innovative source of academic material on transport modelling in semiconductor material and nanoscale devices. Including a range of perspectives on relevant topics such as charge carriers, semiclassical transport theory, and organic semiconductors, this is an ideal publication for engineers, researchers, academics, professionals, and practitioners interested in emerging developments on transport equations that govern information carriers.




Strain-Induced Effects in Advanced MOSFETs


Book Description

Strain is used to boost performance of MOSFETs. Modeling of strain effects on transport is an important task of modern simulation tools required for device design. The book covers all relevant modeling approaches used to describe strain in silicon. The subband structure in stressed semiconductor films is investigated in devices using analytical k.p and numerical pseudopotential methods. A rigorous overview of transport modeling in strained devices is given.




Computational Electronics


Book Description

Starting with the simplest semiclassical approaches and ending with the description of complex fully quantum-mechanical methods for quantum transport analysis of state-of-the-art devices, Computational Electronics: Semiclassical and Quantum Device Modeling and Simulation provides a comprehensive overview of the essential techniques and methods for effectively analyzing transport in semiconductor devices. With the transistor reaching its limits and new device designs and paradigms of operation being explored, this timely resource delivers the simulation methods needed to properly model state-of-the-art nanoscale devices. The first part examines semiclassical transport methods, including drift-diffusion, hydrodynamic, and Monte Carlo methods for solving the Boltzmann transport equation. Details regarding numerical implementation and sample codes are provided as templates for sophisticated simulation software. The second part introduces the density gradient method, quantum hydrodynamics, and the concept of effective potentials used to account for quantum-mechanical space quantization effects in particle-based simulators. Highlighting the need for quantum transport approaches, it describes various quantum effects that appear in current and future devices being mass-produced or fabricated as a proof of concept. In this context, it introduces the concept of effective potential used to approximately include quantum-mechanical space-quantization effects within the semiclassical particle-based device simulation scheme. Addressing the practical aspects of computational electronics, this authoritative resource concludes by addressing some of the open questions related to quantum transport not covered in most books. Complete with self-study problems and numerous examples throughout, this book supplies readers with the practical understanding required to create their own simulators.







Nanoscaled Semiconductor-on-Insulator Structures and Devices


Book Description

This book offers combined views on silicon-on-insulator (SOI) nanoscaled electronics from experts in the fields of materials science, device physics, electrical characterization and computer simulation. Coverage analyzes prospects of SOI nanoelectronics beyond Moore’s law and explains fundamental limits for CMOS, SOICMOS and single electron technologies.




Quantum Transport


Book Description

In this volume, a result of The CIME Summer School held in Cetraro, Italy, in 2006, four leading specialists present different aspects of quantum transport modeling. It provides an excellent basis for researchers in this field.