By Mark Lundstrom

Purdue University

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The transistor is the basic element of electronic systems. The integrated circuits inside today's personnel computers, cell phones, PDA's, etc. contain hundreds of millions of them on a chip of silicon about 2 cm on a side. Each technology generation, engineers shrink the size of transistors by a factor of two, which doubles the number of transistors on a chip. This "device scaling" lowers the cost of the electronic system and increases its performance. Gordon Moore, one of the founders of Intel, noticed in 1965 that the number of transistors per chip doubled each technology generation. He predicted that this doubling of density would continue for some time, but few expected it to continue for 40 years. Today there are 100 transistors for every ant in the world. The resulting exponential growth in the transistor density per chip has made modern electronics possible.

This talk is an elementary introduction to the transistor. It is designed to be accessible to the nonspecialist with a basic understanding of physics. My purpose is to explain how this important device functions and to discuss the challenges that engineers face as they continue to scale down transistor sizes.


Mark Lundstrom is the Don and Carol Scifres Distinguished Professor of Electrical and Computer Engineering at Purdue University where his teaching and research center on the physics, technology, and simulation of electronic devices. Lundstrom is the founding director of the NSF-funded Network for Computational Nanotechnology, which has a mission of research, education, leadership, and service to the nation's National Nanotechnology Initiative. He serves on the leadership councils of the NASA-funded Institute for Nanoelectronics and Computing and the MARCO Focus Center for Materials, Structures, and Devices. Lundstrom’s work has been recognized by several awards, most recently, in 2005, from the Semiconductor Industry Association in recognition of his career contributions to the semiconductor industry.

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Researchers should cite this work as follows:

  • Mark Lundstrom (2004), "Transistors,"

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Purdue University, West Lafayette, IN