The 2002 IEEE Solid-State Circuits Award recipients, Chenming Hu and Ping K. Ko, are being honored for their development of device models used for IC design. The award citation is "for BSIM3 modeling and development work."

Hu and Ko's remarkable research partnership systematically produced physical models for nearly all features of the electrical behavior of modern MOSFETs. The series of MOSFET models they developed for IC simulation are known as BSIM (Berkeley Short-channel IGFET Model).
After a decade of progressive improvement, BSIM3v3 was acknowledged as the world's first and only industry-standard public-domain device model.

In the 1980s and early 1990s Hu and Ko's BSIM1 and BSIM2 models were widely used for IC design. Advanced devices designed and fabricated in the course of their modeling research set MOSFET speed records in 1987 and 1992. The BSIM3 model released in 1995 incorporated more than a dozen physical models and was ground breaking in its accuracy. Its ease of parameter extraction gave users the ability to predict the effect of technology changes and manufacturing variations on MOSFET characteristics.

The BSIM model is almost universal today. Since 1997 all silicon foundry companies, most fabless companies, and most integrated device manufacturers have converted to BSIM. By providing the industry with a standard model, BSIM has streamlined the interactions between corporate partners, and foundries and their clients. Its benefit to industry will make a significant impact for years to come.

Model based on device physics, not curve fitting

A device-compact model should capture and make available to circuit designers all the manifestations of device design and manufacturing variations that may affect circuit performance. The compact model is the principal communication link between technology/manufacturing and design and products. BSIM3 and BSIM4 provide the strong link that IC technology scaling requires.

Hu and Ko, with their students, developed models for velocity saturation, velocity overshoot, mobility degradation, channel electric field, substrate current, gate-induced drain current, output conductance, Vt roll-off, reverse short-channel effect, short-channel intrinsic capacitances, non-quasi-static transient currents, and more. They also co-authored about 200 papers on the physical models of MOSFETs.

Because BSIM3 incorporates many original physical models developed by Hu and Ko, it changed compact modeling from a curve-fitting exercise to sound device physics. For example, it includes the models of three different mechanisms responsible for the output conductance, bias-dependent thickness of the inversion layer, universal mobility, a flicker noise model unifying the carrier and mobility fluctuations, and the non-quasi-static effect, among other effects. BSIM4, released in October 1999, is accurate up to the MOSFET cutoff frequency. This model can be used to design both digital processors and RF circuits. It also introduced the first major new thermal noise model in 20 years.

Their research with others also led to the co-invention of several novel MOS devices, including the Dynamic Threshold MOSFET (DTMOS). In a DTMOS 0.5 V forward bias is applied to the source and body by the gate turn-on signal to lower Vt, increasing circuit speed at very low Vdd. Teaming more broadly provided another co-invention: the source-side-injection flash memory, which uses 1,000 times less programming current and power. Both are used in commercial products.

Their source code is in the public domain

Hu and Ko have provided the source codes of all their models including BSIM3, BSIM4, and BSIMSOI to all users at no cost. The Web site for downloading the codes, test results, benchmark model parameters, and manuals is available for public use. Users do not have to be paid members of an industry trade association or consortium of manufacturers.

In 1996 BSIM3v3 was selected by the Compact Model Council of EIA as the world's first industry standard compact model for IC simulation. The Council promotes the standard model and its members are leading semiconductor and CAD companies such as Intel, IBM, TI, Motorola, HP, AMD, Lucent, Cadence, Mentor Graphics, Sematech, Hitachi, Infineon, Philips, and TSMC. BSIM3v3 also won a 1997 R&D 100 award as one of the year's most significant R&D products.

As the industry need grew, Hu and Ko provided quarterly fixes and annual new releases. Basic technical support for users is provided through an email network of 500 users comprised of numerous simulator vendors that distribute BSIM by embedding it in their simulators.

Hu and Ko continue to update BSIM to serve industry needs. BSIM4 is accurate for RF circuit design for the growing wireless market. Their BSIMSOI model serves another emerging technology and has recently been chosen by IBM for future SOI product design.

Hu earlier was recognized with the IEEE Jack A. Morton Award "For outstanding contributions to the physics and modeling of MOS device reliability." This year's Solid-State Circuit Award recognizes the broad contributions to circuit models. Both Hu and Ko are widely known by their teaching through the University of California Extension and televised National Technological University courses that have reached thousands of engineers over the past 15 years.

In May 2001, Chenming Hu was appointed the first Chief Technology Officer for Taiwan Semiconductor Manufacturing Company. Born in China, Hu holds a B.S. degree in EE from National Taiwan University, and M.S. and Ph.D. degrees in EECS from the UC Berkeley. Before joining the UC Berkeley, in 1976, he was an assistant professor at the Massachusetts Institute of Technology.

In addition to Hu's teaching role, he has been involved in many activities with related industries. He is the co-founder and Co-Chairman of the Board of Celestry Design Technologies, Inc. and was the Nonvolatile Memory Development Manager of National Semiconductor. In addition, he has acted as a consultant to IBM, TI, AMD, Philips and TSMC. He is a member of the U.S. National Academy of Engineering, an IEEE Fellow and a Life Honorary Professor of the Chinese Academy of Science.

Ping K. Ko is Dean of Engineering and Director of Institute for Microsystems at Hong Kong University of Science and Technology. Born in Hong Kong, Ko holds a B.S. degree in physics and an M.S. degree in electrical engineering from Hong Kong University, and a Ph.D. degree in electrical engineering and computer sciences from the UC Berkeley. He was a member of the technical staff at Bell Laboratories and spent 17 years as a professor at the UC Berkeley, where he continues to teach an occasional course. Dr. Ko is a former Chair of the Research Grants Commission of Hong Kong and has served on program committees for the VLSI Technology Symposium and the International Electron Devices Meeting. He received the 1990 Best Paper Award of the International Reliability Physics Symposium. Ko was named IEEE Fellow for contributions to MOS device physics, especially hot carrier effects and device modeling for circuit simulation. He has been honored with an IBM Faculty Development Award and Semiconductor Research Corporation's Technical Excellence Award.

David Hodges
AdCom
IEEE Solid-State Circuits Society
hodges@eecs.berkeley.edu

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