Silicon and Beyond

The following sections are included;

• PREFACE

• CONTENTS

The BSIM3v3 compact MOSFET model is reviewed. It is a physics-based model that is accurate, smooth, continuous, scalable, predictive and computationally robust over different regions of operation and a wide geometry range. BSIM3v3 considers all major physical effects in deep submicron MOSFETs, making it a good base for future sub-0.1m device models and for statistical circuit designs. A key feature of the model lies in its thorough, accurate and functional mathematical representation of MOS device physics, which has made BSIM3v3 selected by an international consortium of semiconductor companies as the first industry standard MOSFET model.

We review recent physics-based, analytical DC models for amorphous silicon (a-Si), polysilicon (poly-Si), and organic thin film transistors (TFTs), developed for the design of novel ultra high-resolution, large area displays using advanced short-channel TFTs. In particular, we emphasize the modeling issues related to the main short-channel effects, such as self-heating (a-Si TFTs) and kink effect (a-Si and poly-Si TFTs), which are present in modern TFTs. The models have been proved to accurately reproduce the DC characteristics of a-Si:H with gate lengths down to 4 μm and poly-Si TFTs with gate lengths down to 2 μm. Because of the scalability of the models and the use of continuous expressions for describing the characteristics in all operating regimes, the models are suitable for implementation in circuit simulators such as SPICE.

We review recent advances in the modeling of novel and advanced semiconductor devices, including state-of-the-art MESFET and HFETs, heterodimensional FETs, resonant tunneling devices, and wide-bandgap semiconductor transistors. We emphasize analytical, physics-based modeling incorporating the important effects present in modern day devices, including deep sub-micrometer devices. Such an approach is needed in order to accurately describe and predict both stationary and dynamic device behavior and to make the models suitable for implementation in advanced computer aided design tool including circuit simulators such as SPICE.

We present a review of modern analog simulation techniques based on time- and frequency-domain algorithms. For time-domain techniques, important topics such as circuit decomposition, relaxation methods, latency, multirate integration, continuation methods, parallel algorithms, and finite difference time-domain methods are discussed. Frequency-domain simulation techniques included are harmonic balance, harmonic relaxation, harmonic-Newton, spectral balance, methods for quasiperiodic circuits, and device modeling for frequency domain simulators. Also included are examples of modern simulators.

The Supercomputer Toolkit is a family of hardware and software modules from which high-performance special-purpose computers for scientific/engineering use can be easily constructed and programmed. The hardware modules include processors, memory, I/O devices and communication devices. The software modules include an operating system, compilers, debuggers, simulators, scientific libraries, and high-level front ends.

When faced with a suitable problem, the engineer/scientist connects the modules by means of static-interconnect technology and constructs a problem-specific parallel computation network. The network is loaded from a workstation that serves as a host. When the program is run, results are collected and displayed by the host. The host handles files, does compilation, etc. The computation network, the Toolkit, does the heavy computation.

In addition to high performance, the advantage of the Toolkit is its low cost which makes it potentially affordable by small groups as their main number crunching computer.

This paper is concerned with the Toolkit version built at the Technion, which is a second generation of the MIT version.¹ The paper briefly describes the hardware and software of this new version and its application to elastic-plastic flow, weather prediction and the simulation of electronic circuits. The main topic of the application section is the relation between the Toolkit configuration and the computation structure of these applications. The paper discusses conclusions related to the hardware and software as well as to the techniques for applying the system.