An engineer should not only acquire knowledge but also make it practical and use it. Thirty years ago, the tools that made the engineering knowledge practical included the drawing board and the slide rule. Nowadays, the tool chest includes computers and engineering software. Out of a great variety of different computer programs, the electronic circuit simulator SPICE is probably the most important for electrical engineers. The SPICE program, originated and developed at University of California at Berkeley, is truly a wonderful present to the electrical engineering community worldwide from one of the best American public universities. It allows us to simulate both individual devices and electronic circuits, performing a large number of different analyses needed for tasks such as verification of circuit designs and prediction of circuit performance. It is so flexible and usually so reliable that many engineers use it as a "software oscilloscope". Several excellent books explain how to use SPICE for circuit simulation and analysis, including those by Vladimirescu, Tuinenga, and Sedra, often used as text books or as supplementary texts for circuit courses.

However, the results of a SPICE simulation are only as good as the device models and the device parameters used in the simulation. Device technologies change so fast and device characteristics are so different that just using default parameters is almost never justified. If wrong device parameters or models are used in a SPICE simulation, all this computer power will be wasted—true to the old adage: "Garbage in, garbage out". Accordingly, it is only natural to link a course in electronic device modeling to SPICE, which is exactly the purpose of the present book: to provide a text for an introductory junior-, senior- or even graduate-level course on SPICE-oriented semiconductor device modeling. (We also envision this book as a useful reference for practicing electrical engineers.) The reader is expected to possess a basic familiarity with semiconductor device physics on the level of, for example, the text by Streetman (1995).

Less than a decade ago, a typical circuit simulator would run only on mainframe computers. However, the rapid progress in microcomputers has enabled the development of SPICE versions that can run on inexpensive machines, making advanced circuit simulators readily available practically to every electrical engineer and electrical engineering student. Hence, we are now in the privileged situation that we can teach a course on the basics of semiconductor device physics and device modeling using the same computer aided design (CAD) tool that electrical engineering students will almost certainly use as practicing engineers. This fortunate circumstance allows students to try actual circuit design, bringing semiconductor device physics and modeling (which are often taught as a fairly theoretical subject) down to a very practical level. Two educational versions of SPICE run on microcomputers—PSpice from Microsim Corporation, and AIM-Spice developed by the authors of this book together with Kwyro Lee. Most examples and problems discussed in this book can be run on either version of SPICE.

This book relies primarily on the circuit simulator AIM-Spice (for IBM PCs and compatibles), and includes basic information on SPICE along with a detailed AIM-Spice manual (AIM-Spice also comes with a comprehensive on-line help support). This makes the book very useful, not only as an introductory text on semiconductor device modeling, but also as a supplementary text for junior-level courses on electronics and circuit theory. The student version of AIM-Spice, can be downloaded from the AIM-Spice home page on Internet. The address is:

AIM-Spice is a version of SPICE with standard SPICE parameters that is familiar to many electrical engineers and electrical engineering students. Running under the Microsoft Windows family of operating systems, it takes full advantage of the available graphics user interface. The program will run on PCs with 80386 or compatible microprocessors with at least 4 MB RAM. However, we recommend using more powerful computers with a 80486 or a Pentium microprocessor and with 8 MB RAM. Even this recommended hardware configuration already looks fairly modest at the moment of writing.

In addition to all the models included into Berkeley SPICE (Version 3e.1), AIM-Spice incorporates many new models for silicon and compound semiconductor devices, such as metal-oxide-semiconductor field-effect transistors (MOSFETs), amorphous silicon and poly-silicon thin film transistors (TFTs), metal semiconductor field effect transistors (MESFETs), heterostructure field effect transistors (HFETs) and heterostructure bipolar transistors (HBTs). The student version of AIM-Spice was used for the device and circuit simulation examples included in the book. A complete professional version of AIM-Spice is available from the authors.

Lee et al. (1993) gave a detailed description of most of the device models used in this new circuit simulator. This book presents a combination of background device physics and technology, a review of existing device models, and, more importantly, a set of new and improved models compatible with the most advanced technology, along with new device characterization techniques for extraction of device parameters. The book was intended to serve as a reference for professional engineers and as a text primarily for a graduate-level course on semiconductor device modeling. Instructors adopting the present book for an introductory course may consider using the advanced book by Lee et al. as their personal reference and, perhaps, as an additional source of problems to be assigned to the students.

Much of the knowledge of software packages is fleeting: You keep up on a particular software package only if you use it on a regular basis. However, once you understand the capabilities and limitations of a program and are provided with a good user's manual, you can get up to speed fairly quickly. Perhaps, the easiest way to get ahead is to use examples that come close to your particular task at hand and modify these examples to suit your needs. Keeping this in mind, we put most of the computer-related information into appendices and provided a large number of examples.

The book is organized as follows: Chapter 1 (Introduction) starts with a simple, motivating example explaining the capabilities and limitations of SPICE simulations. It continues with a historical overview of SPICE and ends with a circuit simulation tutorial intended to quickly enable the reader to understand and operate AIM-Spice. Chapter 2 includes basic semiconductor equations and describes basic material properties of important semiconductors. Chapter 3 is devoted to the modeling of two-terminal devices: p-n junction diodes, Schottky barrier diodes, heterojunctions, and metal-insulator-semiconductor (MIS) capacitors. In Chapter 4, we consider the modeling of bipolar junction transistors, including the HBT. Chapter 5 deals with the operation of and basic model issues of FETs, including the MOSFET, the TFT, and compound semiconductor FETs. The appendices include basic information about SPICE and AIM-Spice.

SPICE (and the AIM-Spice package, in particular) allows students to solve engineering problems, bridging the gap between theory and practice. Many problems included in the book are design problems. These problems do not have unique solutions and involve tradable parameter values.

Most of the problems in the book can be solved (or their analytical solutions can be checked) using AIM-Spice. We believe that students should be encouraged to do just that since AIM-Spice is a state-of-the art VLSI design tool and since real-life problems often do not have analytical solutions.

For a course based on this book, we recommend that two thirds of the credit hours be allocated to engineering design and one third to engineering science.

A detailed solution manual and sets of transparencies for lectures based on this book will be made available for instructors.