Claes Thelander talks with
ScienceWatch.com and answers a few questions about
this month's Fast Breaking Paper in the field of
Engineering.
Article Title: Vertical enhancement-mode InAs
nanowire field-effect transistor with 50-nm wrap
gate
Authors: Thelander,
C;Froberg, LE;Rehnstedt, C;Samuelson, L;Wemersson,
LE
Journal: IEEE ELECTRON DEV LETT
Volume: 29
Issue: 3
Page: 206-208
Year: MAR 2008
* Lund Univ, S-22100 Lund, Sweden.
* Lund Univ, S-22100 Lund, Sweden.
* Qumat Technol AB, Lund 22224, Sweden.
Why do you think your paper is highly
cited?
There is a considerable effort worldwide in trying to find a successor to
the transistor technology that today is based on silicon. The indium
arsenide (InAs) transistor is one candidate, where a narrow semiconductor
bandgap allows for low-power switching and fast operation, which is
particularly important for handheld electronics. We have demonstrated a
fabrication technique and transistor performance that appears very
encouraging for future work in this field.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
"We went through a long period of
“trial and error” to find proper
processing conditions and chemicals that are
compatible with InAs."
The field of nanowires has been very actively researched during the past 10
years, but it has generally been difficult to go from the level of an
individual test device to something that shows promise for upscaling. We
believe that we took the technology one step further by putting many pieces
together, such as implementing a high-k gate dielectric (HfO2),
together with a short wrap-around gate in a vertical transistor geometry.
Would you summarize the significance of your paper in
layman’s terms?
The paper demonstrates that vertical nanowires can be a promising
alternative for future transistors. The transistor itself is based on a
relatively uncommon and expensive material (InAs). However, research by our
group and others has recently shown that nanowires of this material can be
grown on cheap silicon wafers, which means that such high-performance
transistors may also be quite inexpensively produced.
How did you become involved in this research, and were
there any problems along the way?
I have worked in this field for quite some time, but my involvement in the
past has mostly been limited to quantum transport studies of nanowires. My
involvement in the transistor project started when the European Union
launched a collaborative research project in this area. There have indeed been
problems in the project; particularly since InAs is a rather delicate
material from a processing point of view. We went through a long period
of trial and error in order to find proper processing conditions and
chemicals which are compatible with InAs.
Where do you see your research leading in the
future?
We will next look into the high-frequency properties of these transistors,
to see how far we can push the technology. After that we will most likely
look into new types of semiconductors for improved transistor performance,
possibly with the development of new switching processes.
Do you foresee any social or political implications for
your research?
If this research is successful, there is of course a chance that it can
have an impact on the electronics industry, leading to faster and
power-saving electronics. In that sense, I hope that it may have both a
positive economic and environmental impact.
Dr. Claes Thelander
Solid State Physics
Lund University
Lund, Sweden Web