As the devices scale down, even though the absolute noise magnitude gets smaller, since the voltages also scale down, the signal-to-noise ratio decreases. Noise models developed for large area devices based on the large-number-electron averaging theories break down. The lack of accurate models leads the process and circuit designer either to adapt large area-transistor models with high errors or to use a trial-and- error method leading to significant waste of valuable time.

It is well known that low-frequency noise, such as 1/f, generation- recombination (gr), and random telegraph signals (RTS), limits the performance of analog devices. In mixed signal technologies, it has also been shown that the base-band low-frequency noise is up-converted to produce amplitude modulation and phase modulation noise about the carrier signal with side-bands that degrade the spectral purity of the carrier which ultimately limits the system's performance in communication systems. It is essential to characterize, model and minimize the low-frequency noise in these devices to achieve spectral purity at high frequencies. The increasing market demand for RF communication systems has stimulated growth in development of high-speed technologies such as advanced Si homojunction and SiGe heterojunction bipolar transistors, lateral bipolar junction transistors, and graded channel MOSFETs. The existing computer modeling software, SPICE, BSIM, VBIC, MEXTRAM and others, do not have scalable, compact, physics based models for low-frequency noise (1/f, g-r and RTS) observed in advanced CMOS, and Bipolar technologies.

The objectives of our research program address each one of the problems outlined above. We characterize the low-frequency noise behavior of advanced bipolar devices, (including the small emitter-base-area, polysilicon-emitter Si-BJTs, lateral BJTs, and SiGe HBTs) and deep sub-micron CMOS devices (including graded channel MOSFETs);

Based on the obtained data, identify and analyze the mechanisms leading to RTS (both simple and complex) and 1/f noise in these technologies, including charge quantization.

Develop scalable, compact noise models for bipolar, CMOS and BiCMOS technologies that are be incorporated into existing free-domain computer modeling software such as BSIM, VBIC and MEXTRAM.

The program is in collaboration with TI, Motorola, ST-Microelectronics and Legerity. Advanced CMOS devices are supplied by Motorola and ST- Microelectronics. Advanced Bipolars are supplied by ST-Microelectronics, Legerity and TI. Support is provided by THECB through ATP, Texas Instruments through Semiconductor Research Corporation, Motorola, and Legerity.

Zeynep Çelik-Butler received dual B.S. degrees in electrical engineering and physics from Bogaziçi University, Istanbul, Turkey, in 1982. She received the M.S. and Ph.D. degrees in electrical engineering in 1984 and 1987, respectively, from the University of Rochester. She was an IBM Pre-doctoral Fellow from 1983 to 1984, and an Eastman Kodak Pre-doctoral Fellow from 1985 to 1987. She joined the Department of Electrical Engineering at Southern Methodist University in 1987 as an Assistant Professor; was tenured and promoted to Associate Professor in 1993. Dr. Çelik-Butler was the holder of J. Lindsay Embrey Trustee Assistant Professorship from 1990 to 1993. She served as the Assistant Dean of Graduate Studies and Research from 1996 to 1999. She is currently a Professor of Electrical Engineering at University of Texas at Arlington.

She served in various technical committees including 1988, 1989 IEEE-IEDM's and Annual Symposia on Electronic Materials, Processing and Characterization (1989 - 1992) and International Conference on Noise in Physical Systems and 1/f Fluctuations (1993, 1999, 2001). She was the General Chair of TEXMEMS II Workshop. Most recently, she served as the Co-chair for SPIE Symp. on Fluctuations and Noise - Conf on Noise in Devices and Circuits. She is currently a technical editor for Fluctuation and Noise Letters.

She has received several awards including the IEEE-Dallas Section Electron Devices Society Outstanding Service Awards (1995, 1997), IEEE - Electron Devices Society, Service Recognition Award (1995), Outstanding Electrical Engineering Graduate Faculty Awards (1996, 1997, 2001), and SMU-Sigma Xi Research Award (1997).

Her research interests include microelectromechanical systems, infrared detectors, noise in semiconductor and superconductor devices, and high Tc-superconductivity. She has four patents, four book chapters, and over 100 journal and conference publications in these fields.

Dr. Çelik-Butler is a senior member of IEEE, member of Eta Kappa Nu, and the American Physical Society. She is a Distinguished Lecturer for the IEEE-Electron Devices Society.