CMOS Image Sensors: Current Status and Challenges

Charles G. Sodini and Pablo Acosta Serafini

CMOS image sensors have progressed from the research labs in the 1990's to the dominant position in the market place since 2002. The incumbent technology, charge coupled devices, boasted higher spatial resolution, significantly lower noise, and higher dynamic range to faithfully reproduce images with much higher quality than was thought possible in CMOS. In this talk a review of the fundamental concepts that are being practiced in CMOS image sensor design that have led to improvements in all of these dimensions will be described. These technology advancements coupled with the reduced cost of CMOS and the ability to integrate significant electronics on the sensor such as on chip data conversion have made CMOS image sensor one of the fastest growing semiconductor segments today. CMOS image sensor technology has progressed to the point that it is the dominant technology in most digital still cameras with spatial resolutions less than 3MP. It is penetrating the very high end spatial resolution (7-10MP) cameras and has enabled a new fast growing market of camera phones. A review of some of the difficult challenges that are still facing CMOS image sensor design will be discussed.

Bio of Charles Sodini

Charles G. Sodini was born in Pittsburgh, PA in 1952. He received the B.S.E.E. degree from Purdue University, Lafayette, IN, in 1974, and the M.S.E.E. and the Ph.D. degrees from the University of California, Berkeley, in 1981 and 1982, respectively.

He was a member of the technical staff at Hewlett-Packard Laboratories from 1974 to 1982, where he worked on the design of MOS memory and later, on the development of MOS devices with very thin gate dielectrics. He joined the faculty of the Massachusetts Institute of Technology, Cambridge, MA, in 1983, where he is currently a Professor in the Department of Electrical Engineering and Computer Science. His research interests are focused on integrated circuit and system design with emphasis on analog, RF and memory circuits and systems. Along with Prof. Roger T. Howe, he is a co-author of an undergraduate text on integrated circuits and devices entitled "Microelectronics: An Integrated Approach." He also studied the Hong Kong electronics industry and co-authored a chapter with Prof. Rafael Reif in a recent book entitled “Made by Hong Kong.”

Dr. Sodini held the Analog Devices Career Development Professorship of Massachusetts Institute of Technology's Department of Electrical Engineering and Computer Science and was awarded the IBM Faculty Development Award from 1985 to 1987. He was the Associate Director of MIT’s Microsystems Technology Laboratories from 1989-1996. He has served on a variety of IEEE Conference Committees, including the International Electron Device Meeting where he was the 1989 General Chairman. He was the Technical Program Co-Chairman for the 1992 Symposium on VLSI Circuits and the 1993-1994 Co-Chairman of the Symposium. He has served on the Electron Device Society Administrative Committee from 1988-94. He is the past president of the Solid-State Circuits Society and a member of its Administrative Committee. He is a Fellow of the IEEE.

Bio of Pablo M. Acosta-Serafini

Pablo M. Acosta-Serafini received the degree of Electric/Electronic Engineering from the Universidad Católica de Córdoba, Córdoba, Argentina, in 1994, and the M.S.E.E. and Ph.D. degrees from the Massachusetts Institute of Technology, Cambridge, in 1998 and 2004, respectively.

During the summer of 1999, he was with Hewlett-Packard, Corvallis, OR, where he worked on imager characterization procedures. In summer 2000, he was with Agilent Technologies, Corvallis, OR, analyzing potential architectures for megapixel sensors. He is currently a Design Engineer in the Routing and Backplane Solutions group at Analog Devices, Inc., Wilmington, MA. His research interests include high speed signal switching and integrity, CMOS image sensors, and mixed-signal circuits.

Mr. Acosta-Serafini received a National Semiconductor Fellowship in 2000.