Archive for November, 2009

The Bible Has Been Rewritten !

Tuesday, November 17th, 2009

The bible rewritten ? Apparently the answer to this question is YES, at least, the bible for the solid-state imaging engineer got a new edition.  Recently IEEE has published the latest special issue of Transactions on Electron Devices focusing on Solid-State Image Sensors.  After similar publications in August 1985, May 1991, October 1997 and January 2003, this is already the 5th edition of the modern bible.  And as can be noticed, every 6 years a new edition is prepared.  In the late ‘70s, IEEE also published a special issue on Charge-Transfer Devices, but this is not considered as a special issue on image sensors.  In the case the young generation is still interested in the older ED special issues, IEEE has put all Transactions on Electron Devices ever published on a single DVD. 

The latest special issue is guest edited by Eric Fossum together with several guest co-editors (Jerry Hynecek, John Tower, Nobukazu Teranishi, Junichi Nakamura, Pierre Magnan and Albert Theuwissen).  The book contains 29 full-length papers spread over 256 pages.   All papers are grouped in the following categories :

-       Visible spectrum image sensors : several techniques to improve resolution, noise, dynamic range, conversion gain and full well are described.  What a super great performing imager could be made if we could combine all these techniques in a single device … ?

-       Modeling and simulation : also in this group the noise characteristics of the imagers get quite a lot of attention.  Not surprising of course, because noise performance is an important parameter in the definition of the dynamic range of an imager, as well as in the determination of the image quality,

-       On-chip signal and image processing : interesting to read that the CMOS world is still trying to “copy” the TDI architecture introduced many years ago in CCD technology,

-       Emerging technologies and applications : the research on alternative colour imaging techniques is still hot, as well as the retinal implants,

-       X-ray and particle image sensors : the main focus is put on medical applications, in combination with radiation damage effects.

As could be expected, most of the papers deal with CMOS image sensors, but nevertheless, a few CCD papers are included in this special issue (ultra low dark current, high-speed imaging, BSI on high-resistivity).  A nice coincidence with the announcement of the Noble Prize.

Although the quality of the published papers is quite high, it is a bit disappointing to see that the big companies active in the field are not present in this special issue.  Apparently they try to hide the information from their competitors …  Of the big ones active in the consumer imaging business, only Aptina, Toshiba, ST Microelectronics and Texas Instruments are publishing a paper in the special issue on image sensors.  Unfortunately the papers from these 4 companies contain information that was already (partly) presented in other papers or at conferences.  And that is a pitty, the R&D work performed in the large companies is of great quality and quantity.  Hopefully the trend of keeping all that information for themselves will not continue … 

Albert 2009-11-17