MESSAGE
| DATE | 2005-05-23 |
| FROM | Ruben Safir
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| SUBJECT | Subject: [NYLXS - HANGOUT] Transistor Engineering
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ew Mathematical Model Better Describes Transistor Behavior
Penn State and Philips researchers have merged the best features of
their respective approaches to produce a new mathematical model that
describes the behavior of the MOS transistor in a wide class of
integrated circuits found in the majority of electronic devices from
computers to digital watches to communications systems.
Certain circuits can only be simulated accurately using the new
approach, known as the PSP model, including passive mixers used in
mobile phones to increase battery life and current-ratio based circuits
used in analog to digital converters.
In addition, PSP has better RF capabilities than the existing models and
accurately predicts transistor behavior up to frequencies well above 50
GHz.
Dr. Gennady Gildenblat, professor of electrical engineering, leads PSP
development at Penn State. He says, "Fabricating integrated circuits is
expensive and improving them by trial and error adds significantly to
that expense. Accurate models that provide detailed mathematical
descriptions offer engineers the chance to do science-based engineering
and to get it right the first time." Gildenblat will detail PSP in an
invited talk, "Introduction to PSP MOSFET Model," at the Nanotech 2005
International Conference, May 10, in Anaheim, Ca. His co-authors are X.
Li, H. Wang and W. Wu, electrical engineering graduate students at Penn
State, and R. van Langevelde, A. J. Scholten, G. D. J. Smit and D. B. M.
Klaassen, Philips Research Laboratories, The Netherlands.
The key variable in the PSP model is surface potential at the interface
between the silicon and silicon dioxide in the transistor. Since PSP is
based on this physical variable, it yields better predictions of the
behavior of integrated circuits than is possible with alternative
models, especially when devices are miniaturized or are operated at
their limits, the developers say.
Models, such as PSP, which describe transistors in a mathematical way,
are used in circuit simulators. For example, PSP has been tested on a
simulation of a passive mixer, a surprisingly difficult problem that
Gildenblat and others only accomplished recently. In addition, PSP has
been verified against measurements on transistors from various
manufacturers, including those made with the latest technology.
All details of the PSP model are being made available on the Internet.
Philips SIMKit software allows PSP to be directly coupled to many
popular circuit simulators.
Speaking of the Penn State/Philips collaboration, Dr. Dirk Klaassen,
research fellow at Philips Research, says, "Our cooperation brings
together the best fundamental academic and pragmatic industrial
knowledge and expertise on compact modeling. It directly ties our
combined deep understanding of the physical behavior of MOS transistors
onto the requirements set by IC designers and the application areas most
relevant to them."
PSP is being submitted to the Compact Model Council (CMC) as a candidate
for standardization. The Council represents 27 major semiconductor
companies that use models. The Council chooses candidates for
standardization based on the technical needs of its members. The CMC is
scheduled to select a new model for CMOS transistors later this year.
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PSP development was supported, in part, at Penn State by the
Semiconductor Research Corporation, the Motorola Shared University
Partnership Program, the IBM University Partnership Award, Freescale
Semiconductor, and LSI Logic. The development at Philips Research was
supported by the EU Projects IMPACT and NanoCMOS.
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