I can only assume that this spate of ferroelectric "research breakthroughs" is the result of somebody somewhere getting ready to award some R&D grant money. <vbg>
In any case, and at the very least, these last two PR's indicate continuing interest in the development of nano-ferroelectrics for the post CMOS era... And this despite L'Intel's full court press to push 10^8 cycle PCRAM as having a future as anything other than a replacement for massively unprofitable NOR FLASH.
One research project from the Queen's University of Belfast provides a particularly well written abstract suggesting the importance of the nano/quantum dot/self-assembly phase of Ferroelectric memory research:
Abstract: The smooth operation and growth of modern economies is increasingly dependant on memory and data storage. Consequently, technological advancement in this area is of great significance for all of us. A variety of possible future memory technologies are now being driven forward. Amongst these are systems based on ferroelectric capacitors(FeRAM), where the ferroelectric material has the important property that it can be electrically polarised into two possible states. If one state can be read as a '0' then the other state will be a '1' in the conventional binary code that is still used for storing data. FeRAM is comparable to, or potentially better than, all other computer memory technologies in performance, and in addition has the very strong advantage of being 'non-volatile' - in other words when you switch off the power to your computer, the data that you forgot to save will not be lost. However, FeRAM is a still-maturing technology. Despite 2002 being seen as "a coming of age", it will need further development if it is to take over from the mainstream established Si-based systems. It is against this technological backdrop that the applicants seek to embark upon a highly adventurous programme, unlike any that are currently being reported in the global community. We propose a study focusing on two issues: the fabrication of nano-scale (below 100x10^(-9) m) capacitors through self assembly techniques (the capacitors form themselves and are therefore very cheap to make), and the investigation of the functional properties of the resulting nanoscale ferroelectric architectures (the properties of such small ferroelectric units are not well known). Self-assembly of capacitor structures: A novel and attractive way to create both high cell-density and ease in production is to capitalise on self-assembly of nanometre-scale capacitor structures. One of the members of the research team has pioneered work in this field examining the self-assembly of top electrode material on a continuous film of ferroelectric, but other approaches have been to create islands of ferroelectric material on a continuous lower layer. The field is, however, only in its infancy. We propose to take forward the self-assembly of capacitor structures by using a technique developed by our research group in which functionally active materials are deposited onto Si wafers coated in a thin film of porous aluminium oxide (where the pore size is in the nanometre scale range). Key advantages of this technique are that the resulting capacitor structures will be electrically isolated from each other, and their architectures will strongly mirror those used in FeRAM devices currently in production. Evaluation of size-effects in nanometre-scale capacitors: Ferroelectricity is a collective phenomenon - it is only stable if a region of ferroelectric is electrically polarised in the same direction. Hence when the ferroelectric units are made to be small, size-effects on functional behaviour are fully expected. Although considerable exploratory work has been done in the area of size-effects on the functional properties of ferroelectrics, there is still a great deal that is unknown about ferroelectric behaviour at radically reduced dimensions. Reduction of capacitor cell size into the nanometre regime is largely a journey into the unknown. Capacitor cells in ferroelectric computer memory of 0.26 square micro metre should be realised by 2007, and in the longer term this will reduce to 0.0075 square micro metre by 2017. Our proposed research project will allow us to create capacitors of the size envisioned in 2017 now, allowing evaluation of the underlying physics of size effects that will influence devices and technology in general far into the future.
Starts: 01 September 2005 Ends: 31 August 2008 Value (£): 256,446
gow.epsrc.ac.uk
Asian and US research along similar lines is also going on, e.g:
jjap.ipap.jp
pubs.acs.org
When the above Belfast research concludes next year it should go a long way towards suggesting future ferroelectric process development and provide a much better view of its limitations.
This mornings PR from Florida also demonstrates the potential advantages of the natural ferroelectric and anti-ferroelectric states, which PZT exhibits as well as ADP or any other ferroelectric crystal structure. If one could develop a self-assembling F-RAM with such properties it seems at least reasonable to consider the possibility of simply skipping 1T-FRAM entirely and going straight to a "Resistance" FRAM with 0T/0C.
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