Learn the basic properties and designs of modern VLSI devices, as well as the factors affecting performance, with this thoroughly updated second edition. The first edition has been widely adopted as a standard textbook in microelectronics in many major US universities and worldwide. The internationally-renowned authors highlight the intricate interdependencies and subtle tradeoffs between various practically important device parameters, and also provide an in-depth discussion of device scaling and scaling limits of CMOS and bipolar devices. Equations and parameters provided are checked continuously against the reality of silicon data, making the book equally useful in practical transistor design and in the classroom. Every chapter has been updated to include the latest developments, such as MOSFET scale length theory, high-field transport model, and SiGe-base bipolar devices.

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Fundamentals of Modern VLSI Devices

A self-consistent iterative scheme for the numerical calculation of dc potentials and currents in a one-dimensional transistor model is presented. Boundary conditions are applied only at points representing contacts. Input data are: doping profile, parameters governing excess carrier recombination, parameters describing the dependence of mobility on doping and on electric field, applied emitter and collector voltages, and a trial solution for the electrostatic potential. The major limitation of the present approach results from use of Boltzmann rather than Fermi statistics. Convergence of the iteration scheme is good for low and moderate injection levels.

A self-consistent iterative scheme for one-dimensional steady state transistor calculations

J. Y. Tsao,* S. Chowdhury, M. A. Hollis,* D. Jena, N. M. Johnson, K. A. Jones, R. J. Kaplar,* S. Rajan, C. G. Van de Walle, E. Bellotti, C. L. Chua, R. Collazo, M. E. Coltrin, J. A. Cooper, K. R. Evans, S. Graham, T. A. Grotjohn, E. R. Heller, M. Higashiwaki, M. S. Islam, P. W. Juodawlkis, M. A. Khan, A. D. Koehler, J. H. Leach, U. K. Mishra, R. J. Nemanich, R. C. N. Pilawa-Podgurski, J. B. Shealy, Z. Sitar, M. J. Tadjer, A. F. Witulski, M. Wraback, and J. A. Simmons

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Ultrawide-Bandgap Semiconductors: Research Opportunities and Challenges

We present in this paper a compact model of bipolar transistors, suitable for network analysis computer programs. Through the use of a new charge control relation linking junction voltages, collector current, and base charge, the model includes high injection effects. The performance substantially exceeds that of existing models of comparable complexity. For low bias and with some additional idealization, the model reduces to the conventional Ebers-Moll model.

An integral charge control model of bipolar transistors

It is shown that the observed falloff in the f T of a transistor at high currents is due to the spreading of the neutral base layer into the collector region of the device at high current densities. The base layer spreading mechanism derives from an analysis of the effect of the current-dependent buildup of the mobile-carrier space-charge density in the collector transition layer. Calculations show that at sufficiently high collector current levels, the mobile space-charge density in the collector transition layer cannot be considered negligible in comparison to the fixed charge density of that region. The over-all effect of taking the mobile space charge into account in analyzing the collector transition region is that, at high current densities, the transition region boundary adjacent to the neutral base layer is displaced toward the collector metal contact with increasing collector current. The attendant widening of the neutral base layer results in the observed, high-current falloff in f T . The application of this theory to transistor structures of both the alloy and mesa variety yields, in each case, calculated curves of f T vs I c which are in reasonably good agreement with experiment.

A theory of transistor cutoff frequency (f T ) falloff at high current densities

This paper presents a method of analyzing transistor behavior for any base-layer impurity distribution. In particular, expressions are derived for emitter efficiency ?, transverse sheet resistance R, transit time ?, and frequency cut-off f?. The parameters ? and R are functions only of the total number of impurities in the base layer. The analysis is used to derive ?, R, ? and f? for four different distributions-uniform, linear, exponential, and complementary error function. For each of these distributions a transistor base-layer design equivalent in R and f? is obtained. Comparison shows that for equivalent parameters the nonuniform distributions permit the use of wider base layers, but require greater maximum impurity concentrations and must be operated at high current densi

The Dependence of Transistor Parameters on the Distribution of Base Layer Resistivity

The invention of the transistor almost 50 years ago was one of the most important technical developments of this century. It has had profound impact on the way we live and the way we work. The first part of this paper covers the events that led to the discovery of the transistor effect and the invention of the point contact transistor in December of 1947. It continues with the development of the theory of the junction transistor in early 1948 and the fabrication of the first grown junction transistor in 1950. It is fair to say that this event completed the invention of the transistor and developed a fundamental understanding of how it worked. The second part of the paper describes the major hurdles that had to be overcome and the major breakthroughs that had to be made to turn an exciting invention into a far reaching technical innovation. This phase took approximately another 10 years. By that time, high performance, high reliability transistors could be manufactured in large quantity and at low cost. Importantly the foundation had been laid for the invention of the integrated circuit and the dramatic development of the microelectronics industry. The final part of the paper suggests some of the reasons why such an important technological innovation could occur in a relatively short period of time and be such an unqualified success. Finally, there are some comments on how much further this technology can go and when its rapid progress may come to an end.

The invention of the transistor

Unipolar "field-effect" transistors of a type suggested by W. Shockley have been constructed and tested. The idealized theory of Shockley has been extended to cover the actual geometries involved, and design nomographs are presented. It is found that these structures can be designed in such a way as to yield a negative resistance at the input terminals. The characteristics of several units are presented and analyzed. It is shown that these characteristics are in substantial agreement with the extended theory. Finally a speculative evaluation of the possible future applications of field effect transistors is made.

I. M. Ross

Papers

The Dependence of Transistor Parameters on the Distribution of Base Layer Resistivity

The invention of the transistor

Unipolar "Field-Effect" Transistor