By Topic

The evolution of IBM CMOS DRAM technology

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $31
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

15 Author(s)
Adler, E. ; IBM Microelectronics Division, Burlington facility, Essex Junction, Vermont 05452, USA ; DeBrosse, J.K. ; Geissler, S.F. ; Holmes, S.J.
more authors

The development of DRAM at IBM produced many novel processes and sophisticated analysis methods. Improvements in lithography and innovative process features reduced the cell size by a factor of 18.8 in the time between the 4Mb and 256Mb generations. The original substrate plate trench cell used in the 4Mb chip is still the basis of the 256Mb technology being developed today. This paper describes some of the more important and interesting innovations introduced in IBM CMOS DRAMs. Among them, shallow-trench isolation, I-line and deep-UV (DUV) lithography, titanium salicidation, tungsten stud contacts, retrograde n-well, and planarized back-end-of-line (BEOL) technology are core elements of current state-of-the-art logic technology described in other papers in this issue. The DRAM specific features described are borderless contacts, the trench capacitor, trench-isolated cell devices, and the “strap.” Finally, the methods for study and control of leakage mechanisms which degrade DRAM retention time are described.

Note: The Institute of Electrical and Electronics Engineers, Incorporated is distributing this Article with permission of the International Business Machines Corporation (IBM) who is the exclusive owner. The recipient of this Article may not assign, sublicense, lease, rent or otherwise transfer, reproduce, prepare derivative works, publicly display or perform, or distribute the Article.  

Published in:

IBM Journal of Research and Development  (Volume:39 ,  Issue: 1.2 )