THE ELECTRONIC ALADDIN NEWSLETTER NO. 28

January/May 2001

1. LEAPFROGGING THE MICROCIRCUIT PATTERN-SIZE BARRIER

Scientists at the Center for NanoTechnology (CNTech) have used the radiation from the SRC in a unique way for a new approach to next generation lithography. The Bright Peak Enhanced Phase Mask (BPEXPM) approach funded by DARPA uses the X-rays from the storage ring to demonstrate printing of 50 nm to 30 nm features that correspond to the years 2007 and 2011 in the International Technology Roadmap for Semiconductors. The new X-ray lithography approach truly opens the possibility for leapfrogging the Roadmap in the fabrication of microprocessor and low-density microcircuit applications. It also opens the field to higher-speed microwave communication devices.  The method is based on a new way to apply the principle of phase masks to enhance the intensity that is produced from a clear edge phase mask structure that can be fabricated with normal semiconductor processing. In the new development, both edges of the clear edge phase mask are coupled to produce an enhancement of the bright peak where the feature on the mask is larger by a factor of 5-6 than the feature that is printed on the wafer. For example, a 320 nm mask feature has been simulated and experimentally shown to print a 54 nm feature on the wafer at substantially larger gaps than conventionally used in X-ray lithography.

 

2. QUANTUM PHENOMENA DETERMINE LAYER STABILITY

As the physical size of the structures that can be fabricated with the best nanotechnology techniques approaches atomic dimensions, one expects quantum electronic effects to appear. For example, there have been predictions and observations of "magical" sizes of atomic clusters with closed electron shells. The analog of this effect in thin films are magical thicknesses which are related to standing electron waves (quantum well states) that match the thickness of the films. This connection is made in a recent article by Dah-an Luhand coworkers at the U. Illinois Urbana-Champaign and other institutions (Science 292, 11 May 2001. p. 1131).They are able to prepare atomically-perfect films of silver on fine iron whiskers and to measure the standing electron waves at the SRC by photoemission. Each number of atomic layers has a characteristic energy spectrum of quantum well states. When heating up the silver films gently, only the most stable configurations survive. In this case, the magic numbers are 2 and 5 atomic layers, in agreement with the numbers calculated from the quantum well states.

 

3. GADOLINIUM BRAIN CANCER THERAPY GAINING GROUND

Gelsomina "pupa" De Stasio of the UW-Madison has been pursuing a cure for brain cancer (glioblastoma), a particularly nasty type of cancer that regrows extremely quickly, even if only a few cancer cells remain after surgery. Gadolinium neutron capture therapy (GdNCT) is a non-invasive experimental therapy for brain cancer, never tested on human or animal cases. It is based on two steps: first the patient is intravenously injected with a benign tumor-seeking gadolinium compound; second, the patient's brain is exposed to thermal neutrons, which induce a nuclear reaction that damages the DNA of the tumor cells and kills them. This idea works only if the gadolinium can be selectively adsorbed by the nuclei of the tumor cells and not by nearby healthy tissue. That has been the big question, and unsuccessful attempts with a similar therapy based on boron have cast doubt on its feasibility.  In a recent article (Cancer Research 61, 4272, May 15, 2001) she teams up with radiobiologists and medical doctors to show that a special, gadolinium-containing compound penetrates the plasma membrane and accumulates in cell nuclei. Previous MRI work had shown the selective uptake in cancer cells over normal cells.  Her photoelectron microscope at the SRC was instrumental in finding how the gadolinium is distributed inside a cell.

4. MARCH 25 OPEN HOUSE A SUCCESS

The SRC hosted another successful Open House on March 25. Building on last year's Open House we had 259 participants including 77 young folk.  Participants had a chance to take part in basic science activities and demonstrations such as "Recipe for doing science at the SRC," "Atoms in Motion," and, "The Nature of Light." Tours were offered which included basic explanations of how the Aladdin ring works and the research that is done here at the SRC. We received many positive comments (65% gave us feedback) including such comments as: "Learning about science is always amazing and exciting," "I could probably spend hours here listening about the work done here. It was great. Thank you," and, "This was a rare privilege!" For more information please visit our web site at http://www.src.wisc.edu/outreach/ .

 

5. NEXT BEAMTIME PROPOSAL DATE IS AUG. 1, 2001

The next opportunity for SRC beamtime proposals is for the August 1stdeadline. Detailed information and a Word template can be downloaded from the SRC Web site at http://www.src.wisc.edu/user_info/forms/beamtime/beamtime_proposals/

 

6. SRC HOSTS 2001 SRI CONFERENCE

The 12th U.S. National Synchrotron Radiation Instrumentation Conference will be hosted by SRC August 22-24, 2001. In addition to the U.S. facilities, LNLS in Campinas, Brazil and the CLS in Saskatoon, Canada have agreed to participate, thus strengthening the ties between synchrotron radiation communities in the Americas. The conference will include oral and poster presentations related to recent developments in synchrotron sources, instrumentation, experimental techniques, detectors, IR advances, beamline optics, lithography, and other exciting areas of synchrotron research. Workshops are being held on the use of Energy Recovery Linacs as sources of synchrotron radiation and Source Stability Requirements for existing and future facilities. In addition, a round table discussion will be held concerning the results of a recent workshop on Detectors for Synchrotron Radiation and the progress in creating a roadmap for development of next generation synchrotron detectors.  The deadline for early registration is July 1, 2001! Registration includes admission to all talks and poster sessions, the conference banquet, a picnic and tour of SRC, and a copy of the proceedings to be published in the Review of Scientific Instruments. For more information see our website at http://www.src.wisc.edu/SRI2001/

 

7. 2001 USERS MEETING

The annual SRC Users Meeting will take place on Friday Oct. 12 and in the morning of Oct. 13. It includes presentations and a poster session on Friday afternoon. All Users are encouraged to present a poster and to submit a one-page abstract about their recent work at SRC. This Users' Meeting is a great opportunity to learn more about the current research conducted at SRC and future research opportunities. Information will be posted at http://www.src.wisc.edu.

8. SOLICITATION FOR ALADDIN LAMP AWARD NOMINATIONS

The Aladdin Lamp Award recognizes excellence in synchrotron radiation research performed at the SRC as part of an educational program. There is no restriction on the level of the degree at this time. The winner will be announced at the SRC Users Meeting (Friday Oct. 12). For details of the application consult the SRC Web page at http://www.src.wisc.edu/news/Aladdin_Award/announcement.html . Deadline is August 31.

 

9. NEW NSF ACKNOWLEDGMENT

With the renewal of the SRC comes a new DMR number. The suggested acknowledgment in SRC related publications is the following: This work is based upon research conducted at the Synchrotron Radiation Center, University of Wisconsin-Madison, which is supported by the NSF under Award No. DMR-0084402.

 

10. CONGRATULATIONS TO SRC RESEARCHERS

Gelsomina "pupa" De Stasio was knighted at the Italian Consulate in Chicago on June 1, 2001 upon a personal initiative of the President of Italy. Pupa said "I'd rather be knight of the periodic table!".