Preface
Dept. of Electrical and Computer Engineering
SUNY–Stony Brook, Stony Brook, NY 11794, U.S.A.
Division of Engineering, Brown University, Providence, RI 02912, U.S.A.
This book is a brainchild of the sixth workshop in the Future Trends in Microelectronics series (FTM-6). The first of the FTM conferences, “Reflections on the Road to Nanotechnology”, had gathered in 1995 on Ile de Bendor, a beautiful little French Mediterranean island.1 The second FTM, “Off the Beaten Path”, took place in 1998 on a larger island in the same area, Ile des Embiez.2 Instead of going to a still larger island, the third FTM, “The Nano Millennium” went back to its origins on Ile de Bendor in 2001.3 To compensate, the next FTM, “The Nano, the Giga, the Ultra, and the Bio” took place on the biggest French Mediterranean island of them all, Corsica.4 Normally, the FTM workshops gather every three years; however, the FTM-4 was held one year ahead of the usual schedule, in the summer of 2003, as a one-time exception. Continuing its inexorable motion eastward, the fifth FTM workshop, “Up the Nano Creek”, had convened on Crete, Greece, in June of 2006.5 The inexorable motion was then interrupted to produce a semblance of a random walk in the Mediterranean and the last workshop, FTM-6 “Unmapped Roads” went to the great Italian island of Sardinia (June 2009).
The FTM workshops are relatively small gatherings (less than 100 people) by invitation only. If you, the reader, wish to be invited, please consider following a few simple steps outlined on the conference website. The FTM website at www.ece.sunysb.edu/~serge/FTM.html contains links to all past and planned workshops in the series, their programs, publications, sponsors, and participants. Our attendees have been an illustrious lot. Suffice it to say that among FTM participants we find five Nobel laureates (Zhores Alferov, Herbert Kroemer, Horst Stormer, Klaus von Klitzing, and Harold Kroto) and countless others poised for a similar distinction. To be sure, high distinction is not a prerequisite for being invited to FTM, but the ability and desire to bring fresh ideas is. All participants of FTM-6 can be considered authors of this book, which in this sense is a collective treatise.
The main purpose of FTM workshops is to provide a forum for a free-spirited exchange of views, projections, and critiques of current trends and future directions, among the leading professionals in industry, academia, and government. It is a common view among the leading professionals in micro-electronics, that its current explosive development will likely lead to profound paradigm shifts in the near future. Identifying the plausible scenarios for the future evolution of microelectronics presents a tremendous opportunity for constructive action today.
For better or worse our civilization is destined to be based on electronics. Ever since the invention of the transistor and especially after the advent of integrated circuits, semiconductor devices have kept expanding their role in our lives. Electronic circuits entertain us and keep track of our money, they fight our wars and decipher the secret codes of life, and one day, perhaps, they will relieve us from the burden of thinking and making responsible decisions. Inasmuch as that day has not yet arrived, we have to fend for ourselves. The key to success is to have a clear vision of where we are heading.
Some degree of stability is of importance in these turbulent times and should be welcome. Thus, although the very term “microelectronics” has been generally re-christened “nanoelectronics”, we have stuck to the original title of the FTM workshop series.
The present volume contains a number of original papers, some of which were presented at FTM-6 in oral sessions, other as posters. From the point of view of the program committee, there is no difference between these types of contributions in weight or importance. There was, however, a difference in style and focus -and that was intentionally imposed by the organizers. All speakers were asked to focus on the presenter's views and projections of future directions, assessments or critiques of important new ideas/approaches, and not on their own achievements. This latter point is perhaps the most distinctive feature of FTM workshops. Indeed, we are asking scientists not to speak of their own work! This has proven to be successful, however, in eliciting powerful and frank exchange. The presenters are asked to be provocative and/or inspiring. Latest advances made and results obtained by the participants are to be presented in the form of posters and group discussions.
Each day of the workshop was concluded by an evening panel or poster session that attempted to further the debates on selected controversial issues connected to the theme of the day. Each such session was chaired by a moderator who invited two or three attendees of his or her choice to lead with a position statement, with all other attendees serving as panelists. The debate was forcefully moderated and irrelevant digressions cut off without mercy. Moderators were also assigned the hopeless task of forging a consensus on critical issues.
All FTM workshops adhered to these principles in the past and, hopefully, will do so in the future. To accommodate these principles, the FTM takes a format that is less rigid than usual workshops to allow and encourage uninhibited exchanges and sometimes confrontations of different views. A central theme is designed together with the speakers for each day. Another traditional feature of FTM workshops is a highly informal vote by the participants on the relative importance of various fashionable current topics in modern electronics research. This tradition owes its origin to Horst Stormer, who composed the original set of questions and maintained the results over four conferences. These votes are perhaps too bold and irreverent for general publication, but they are carefully maintained and made available to every new generation of FTM participants. Unfortunately, Horst missed the Sardinia gathering, but the tradition was maintained in his absence. Another traditional vote concerned the best poster. The 2009 winning poster was “Heterogeneous integration of nanowires and nanotubes on CMOS” by Sameer Sonkusale.
From all the deliberations and discussion at FTM-6 the following trends could be discerned, with the caveat that our crystal ball is as muddy as ever.
Firstly, although silicon is undoubtedly still full of steam, the word “post-CMOS” has become a commonplace. Several FTM-6 presentations included the expression “beyond silicon” in the title. A clearly discernible trend is the quest for novel and exotic materials, as well as utilization of nanoscale phenomena. It looks like we are back to fundamentals. The big-brother silicon is clearly pressed (at least in terms of the conference publicity) by its much nimbler sibling carbon, which is capable of producing graphene sheets with miraculous properties. Germanium is another column-IV element that is challenging silicon at its own game. Away from column-IV materials, we can single out an exciting report describing the superconducting processors and systems based on the rapid single flux quantum (RSFQ) circuit technology.
Among other - perhaps niche - materials, discussed at the workshop, we find chalcogenide glassy semiconductors for memory applications and vanadium dioxide that undergoes semiconductor-to-metal transition above room temperature. It turns out that in VO2 films the hysteresis of this transition can be tamed to yield reproducible linear excursions suitable for bolometric applications.
Secondly, a sizeable part of the discussion at FTM-6 was devoted to optoelectronics, most notably to nanophotonics issues, such as photonic crystals, plasmonics, and terahertz cascade lasers. Several authors discussed applications of nanophotonics in optical interconnects and communications. This topic is traditional for FTM but the emphasis on nanophotonics is a discernible new trend.
Finally, a noteworthy fraction of the discussion at our microelectronics workshop dealt with macro electronics, such as flat panel displays, solar cells, and bioelectronics sensors. For such systems, the guiding principles are cost (the smaller the better) and often the size (the larger the better!). A new topic for FTM was the discussion of high-energy radiation sensors. Development of gamma detectors, capable of isotope discrimination and the determination of the direction to source, is a very timely challenge, especially in homeland security applications. The FTM-6 workshop had included a mini-symposium on gamma radiation sensors, and three papers presented at that symposium have made it into this volume. The purpose of the gamma-radiation symposium was to acquaint the traditional FTM audience with the basic issues of radiation detection, in hope of recruiting new blood to address issues in the nuclear-engineering field that have become timely in the face of the new challenge. Presentations at the symposium were therefore somewhat pedagogical in nature.
Not every contribution presented at FTM-6 has made it into this book (not for the lack of persistence by the editors). We sorely miss the exciting contribution by Mark Pinto, a “captain of industry” from Applied Materials, who spoke on large-scale photovoltaics. Abstracts of his and all other presentations can be found on the workshop program webpage, http://www.ee.sunysb.edu/~serge/ARW-6/program.html
The FTM meetings are known for the professional critiques - or even demolitions - of fashionable trends, that some may characterize as hype. The previous workshops had witnessed powerful assaults on quantum computing, molecular electronics, and spintronics. The majority of FTM participants did not consider quantum computing a realistic future technology, but gave it credit as an interesting playground for physicists with some hope of settling old debates about the wavefunction collapse and other fundamental issues. It seems that by now most of the hype associated with quantum computing has dissipated and perhaps we can take some credit for the more balanced outlook that has emerged since.
Another characteristic of FTM meetings is the settling of scientific bets, a tradition that dates back to the FTM-2 wager between Nikolai Ledentsov (for) and Horst Stormer (against) the coming dominance of quantum dot-based lasers - a bet that Horst collected in 2004, at FTM-4. At FTM-6, the two bets coming due were on the relative strength of personal computer-based chess programs versus the human world champion (the bettors were Serge Luryi for the humans and Alex Zaslavsky for the PCs) and the predicted capture of half of the Si technology market by SiGe devices (the bettors were Erich Kasper for SiGe and Sorin Cristoloveanu against). Confronted with the evidence of a modern PC beating grandmasters even while starting a pawn down, Serge conceded at the workshop, whereas Erich had to concede long-distance. Yet another bet on the putative future dominance of SOI technology was made at FTM-6, to be adjudicated at a future workshop.
We have grouped all contributions into four chapters, entitled I. Optoelectronics and nanophotonics; II. Electronic devices and systems; III. Physics, biology, and other sister sciences; and IV. Sensors, detectors, and energy. The breakdown could not be uniquely defined, because some papers fit two or even three categories! To produce a coherent collective treatise out of all of this, the interaction between FTM participants had begun well before their gathering at the workshop. All the proposed presentations were posted on the web in advance and could be subject to change up to the last minute to take into account peer criticism and suggestions. After the workshop is over, these materials (not all of which have made it into this book) remain on the web indefinitely, and the reader can peruse them starting at the www.ece.sunysb.edu/~serge/FTM.html home page.
Acknowledgments
The 2009 FTM workshop on Sardinia and therefore this book were possible owing to support from:
• U.S. Department of Defense: ARO, DTRA, ONR;
• U.S. DoD European offices: EOARD, ONR-Global;
• NRC of Canada (Institute for Microstructural Sciences);
• Industry: Applied Materials Inc.;
• Academia: SUNY-Stony Brook, The World-Class University Program at the Seoul National University.
On behalf of all Workshop attendees sincere gratitude is expressed to the above organizations for their generous support.
Finally, the organizers wish to thank all of the contributors to this volume and all the attendees for making the workshop a rousing success.
References
1. S. Luryi, J. M. Xu, and A. Zaslavsky, eds., Future Trends in Microelectronics: Reflections on the Road to Nanotechnology, NATO ASI Series E Vol. 323, Dordrecht: Kluwer Academic, 1996.
2. S. Luryi, J. M. Xu, and A. Zaslavsky, eds., Future Trends in Microelectronics: The Road Ahead, New York: Wiley Interscience, 1999.
3. S. Luryi, J. M. Xu, and A. Zaslavsky, eds., Future Trends in Microelectronics: The Nano Millennium, New York: Wiley Interscience/IEEE Press, 2002.
4. S. Luryi, J. M. Xu, and A. Zaslavsky, eds., Future Trends in Microelectronics: The Nano, The Giga, and The Ultra, New York: Wiley Interscience/IEEE Press, 2004.
5. S. Luryi, J. M. Xu, and A. Zaslavsky, eds., Future Trends in Microelectronics: Up the Nano Creek, New York: Wiley Interscience/IEEE Press, 2007.