| Forum |
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| Exploring technology in Silicon Hills |
| by Stefan Zollner and Stephen Rosenblum |
The American Physical Society (APS) will hold its 2003
March meeting March 27 in Austin, Texas, the hub of an
area known in the semiconductor industry as Silicon Hills. Appropriate
to the setting, the APSs
Forum on Industrial and Applied Physics (FIAP) will focus much
of its annual program at the meeting on topics of particular interest
to the computer, microelectronics, nanotechnology, equipment, and
instrumentation companies that make up the local high-tech community.
Most of the 2 tutorials, 18 focus sessions, and 12 invited symposia
will assess the state of leadingedge investigations and challenges
in heterostructures, semiconductors, nanoscale science, and physics
issues in silicon microelectronics.
Heterostructures
On Sunday, March 2, there will be a pre-meeting tutorial titled
Heterojunctions Everywhere, an event suggested by
FIAP and designed to examine in breadth the role and importance
of these semiconductor junctions between two dissimilar materials.
Nobel laureates Herbert Kroemer of the University of California,
Santa Barbara, and Horst Stormer of Columbia University and
Lucent Technologies Bell Laboratories will give an overview
of heterojunction physics and its application to semiconductor
devices. Heterostructures enable the study of the physics of
two-dimensional systems as well as the demonstration of fascinating
phenomena, such as the fractional quantum Hall effect. Federico
Capasso of Bell Laboratories will review the invention of the
quantum cascade laser, an optoelectronic device based on heterostructures,
and the process of bringing it to market. Chris van de Walle
of Xeroxs Palo Alto Research Center will describe how
structural changes and strain affect the electronic band alignment
at the interface between two semiconductors and the application
of these effects to commercial devices (Figure 1, right). |
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| Figure 1. In this simulation
from Chris van de Walles work at Xerox, an ammonia
molecule (nitrogen atoms are green, hydrogen gray, and
the filled orbital pink) approaches a gallium nitride
surface (gallium is blue, and the empty danglingbond orbital
on the surface of the gallium atom is yellow). (Chris
van de Walle, Xerox Palo Alto Research Center) |
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Two invited symposia and one focus session (IR Applications
of Semiconductor Nano- and Microstructures)held during the
regular APS programwill complement the tutorial. The symposium,
Applications of Semiconductor Heterostructures, will
describe their commercial uses. In this session, Karl Johnson, director
of Motorolas Compound Semiconductor Technology Laboratory,
will explain the advantages of an indium gallium phosphide heterojunction
bipolar transistor, first proposed by Kroemer in 1983, as a high-frequency
power amplifier in a cellular telephone, and what the competing
device technologies are. Other invited talks in this session will
describe column-IV semiconductor heterostructure devices, applications
of the 6.1-Å-lattice-constant family of semiconductors (particularly
antimonides for infrared detectors), and quantum cascade lasers.
A related symposium will explore the critical role of heterostructures
in nanostructured interfaces. Topics in this invited session will
range from ab initio theory and modeling of interfaces, to atomic-resolution
imaging using transmission electron microscopy, to atomiclayer deposition
of high-dielectricconstant (high-k) gate dielectrics for
future silicon complementarymetal- oxide-semiconductor (CMOS) devices.
This highly technical program will be augmented by a networking
breakfast that FIAP will co-sponsor with APSs Committee on
the Status of Women in Physics, which will feature a local leader
in high technology as the keynote speaker.
Semiconductors
Another emphasized theme of the FIAP program will examine the physics
problems encountered on the International Technology Roadmap for
Semiconductors (ITRS), a periodic assessment of the semiconductor
industr ys technical needs over the next 15 years and the
challenges it confronts in meeting them. Frontiers in Si CMOS,
an invited session organized jointly by FIAP and the Group on Instrumentation
and Measurements, will introduce the ITRS roadmap and point out
the technical challenges. These problems include the characterization
and measurement of high-k gate dielectrics, metal interconnects,
and low-k interlayer dielectrics.
Other speakers at this session will address R&D Strategies
for the Semiconductor Industry, Frontiers of Physics
in Low-k/Interconnect Research, X-ray Measurements
for the Semiconductor Industry, and Beyond Classical
CMOS Devices: A Wild West Physics Frontier.
A related symposium, Microelectronics Modeling and Simulation",will
describe the role of condensed-matter theory and first-principles
device modeling in the microelectronics industry. These two symposia
and several related focus sessions form a miniconference. The related
sessions cover a range of topics: "Measurements and Instrumentation
for the Semiconductor Industry", "Mechanical Properties
of Nanostructured Thin Films and Coatings", "Front-End
Materials and Processes for Scaled Si CMOS", "Novel Complex
Oxides", "Progress in Photovoltaic Technology", "Optical
Telecommunications", "MEMS/NEMS Science and Technology",
and "Physics of Silicon in Electronic Materials".
Nanostructures
The National Nanoscale Initiative (NNI) links 16 U.S. departments
and independent agencies in an effort to increase and enhance research
in nanoscale science. Since NNI¡'s inception in early 2000,
the National Science Foundation (NSF) and other funding agencies
have made large investments in nanoscale science and technology.
In September 2001, for example, NSF established Nanoscale Science
and Engineering Centers (NSECs) at six universities.Columbia, Cornell,
Harvard, Northwestern, Rice, and Rensselaer Polytechnic Institute
(RPI).
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| Figure 2. Image of the coherent flow
of electrons through a quantum point contact formed in
a two-dimensional electron gas inside a gallium arsenide/aluminum
gallium arsenide heterostructure. (Robert Westervelt and
Eric Heller at Harvard University, Arthur C. Gossard at
University of California, Santa Barbara) |
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In a session organized by Ulrich Strom of NSF¡'s Division
of Materials Research, the directors or other senior researchers
at the six NSECs -- Robert Buhrman, Vicki Colvin, Mark Hersam,
Richard Siegel, Horst Stormer, and Robert Westervelt (Figure
2). will present highlights of early research results from
their facilities. They will also describe opportunities to
translate scientific discovery into innovative technological
products. FIAP and the Division of Condensed Matter Physics
will be co-sponsors of this session.
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This nanoscience symposium is complemented by a FIAP focus session,
Understanding Molecular and Nanoelectronics, which continues a successful
series of sessions held at last year's APS March meeting. Contributed
papers will describe progress in theoretical and experimental methods
in this area. Topics are expected to include quantum-size effects
in the contact interaction between a molecule or atom and a surface,
charging of the molecule near a surface, and the scattering of charge
carriers at the solid.molecule interface. APS's Division of Materials
Physics (DMP) is organizing a related focus session on transport
in nanostructures and ultrathin films.
Career building
FIAP and the APS Committee on Careers and Professional Development
(CCPD) will present a second Sunday tutorial, titled "Things
Your Professors Will Never Tell You". It aims to explain career
choices to physics graduate students, postdoctoral fellows, and
assistant professors without tenure who need to choose between traditional
academic positions and jobs in industry. The instructors will be
experienced physicists from industry and universities, who are familiar
with these choices and can discuss the opportunities and the consequences
of early decisions later in one's career. In particular, there will
be an emphasis on career transitions from university to industry
and back, moving from individual contributor to management, and
the influence of industrial experience in obtaining funding for
university research projects.
A symposium titled "Training Physics Students for the Semiconductor
Industry", also jointly organized by FIAP and CCPD, will continue
with this theme. In this invited session, Mark Holtz from Texas
Tech University will describe several successful interdisciplinary
programs that place physics students studying for a master's degree
in industrial internships. Two university professors, Mark Law from
the University of Florida and Toh Ming Lu from RPI, will discuss
the role of funding from the semiconductor industry, through the
Semiconductor Research Corp., on physics and engineering education.
Larry Larson from International Sematech and Brad Melnick from Motorola,
two senior industrial scientists, will describe their hands-on experiences
in the semiconductor industry.
As always, the FIAP program encompasses a broad range of other
topics. These sessions include a symposium addressing the Economic
Value of Research, organized by FIAP and the Forum on Physics and
Society. Together with the Division on Biological Physics, FIAP
will present a symposium on "Advances in Medical Imaging for
Early Cancer Detection", and another symposium, organized by
FIAP and DMP, will discuss "Nitride Semiconductors for Solid-
State Nitrides and Other Applications". A Thursday evening
session, "Physics in the Entertainment Industry", will
offer insightful comments on such topics as interstellar travel,
alien life forms, and crop circles. The
complete list of FIAP programs is accessible at the APS Web site,
by either following the link to the FIAP home page or going to the
APS March meeting pages.
Stefan Zollner
is section manager of wireless technology analysis at Motorola's
Advanced Process R&D Laboratory in Tempe, Arizona, and FIAP
program committee chair.
Stephen Rosenblum
is a senior scientist at Advanced Energy Industries in San Jose,
California, and FIAP newsletter editor.
For more information on FIAP, please
visit the FIAP Web site or contact the chair, Gordon
Thomas.
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