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Facilities
Novel
UHV Depostion and Stress Measurement System | Vacuum
Evaporation System | Substrate Curvature
Stress Measurement System | Atomic Force Microscope | Scanning Nanoindenter |
X-ray Microtensile Tester | X-ray Thermal Strain Measurement
System | Other Facilities at Cornell University | Facilities at Other Institutions
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| As decribed in our page on group research
projects, a wide array of experimental and computations
facilities are available to Baker group members. A description
of facilities that are available in the Baker group, as well
as links to multi-user facilities that we use follow: |
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Novel UHV
Depostion and Stress Measurement System
This unique ultra high vacuum (UHV) system consists of 4
chambers as shown below. From left to right: The load lock
allows us to insert and remove samples without ventilating
the system and includes a cassette for 8 wafers. The transfer
chamber with 6 ports allows us to move samples among experimental
stations without leaving the UHV environment. It includes
an internal cassette for storage of 8 samples and a "substrate
flipper" that allows us to turn samples over for backside
depostions.The deposition chamber includes ports for
up to 5 confocal magnetron sputter guns, evaporation cells,
or ion sources. It is currently equipped with 2 magnetrons.
Samples can be heated to approx 600°C, biased, and rotated
during deposition. Gas flow controllers allow reactive deposition.
A central window in the bottom of the chamber allows stress
measurements in situ during deposition. The stress
measurement chamber contains a resistively heated and
water cooled chamber in which samples are heated and cooled
between room temperature and 800°C while stress measurements
are made using an optical stress measurement system (not shown)
described below.
The system handles bare 4" substrates or
smaller samples mounted to 4" plates throughout and is
capable of vacuum levels below 10-9 torr throughout.
This system was designed and engineered to our specifications,
and was built by SURFACE,
in Hückelhoven, Germany.
The main use of this system is to deposit thin
film systems with very good control over composition and interface
chemistry and to measure the thermomechanical behavior of
these systems in situ so that interface chemistry can
be conrolled during thermal cycling as well.
This system was substantially funded by an award
from the U.S. Office of Naval Research (N00014-99-1-06650)
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Vacuum Evaporation
System
This system contains thermal and e-beam evaporation sources,
an ion gun, and rate controllers. Ion-beam assisted deposition
(IBAD) and reactive evaporation are possible with this system.
It is used to deposit a range of metal and metal nitride
films on silicon, glass, and polymer substrates. We share
this equipment with the research group of Prof.
Yuri Suzuki.
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Substrate Curvature Stress
Measurement System
In this system, a laser scanning method is used to determine
the curvature induced in a film/substrate package by a stress
interaction between the film and substrate (e.g. due to differential
thermal expansion). By use of an appropriate model, it is
possible to determine the stress in the film from the changes
in curvature. We have built and rebuilt several substrate
curvature stress measurement systems in recent years. Recently,
we have come up with a unique design that will allow us to
scan in two dimensions to get the full shape of the substrate
and which is quite fast. We will be using it in our UHV deposition
system, and are also building a stand-alone system.
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Atomic Force Microscope
We have a Digital
Instruments Nanoscope III that we use for imaging and
analysis of samples. We also use this machine as a platform
for our scanning nanoindenter system (see below). We share
this equipment with the research group of Prof.
Yuri Suzuki. This equipment was partially purchased with
funds supplied by the National Science Foundation under the
"Instrumentation for Materials Research" program
(DMR-9975924).
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Scanning Nanoindenter
In this instrument, the normal displacement sensing system
of our AFM (above) is removed and is replaced with a transducer
as shown below. This transducer is capable of both applying
loads and measuring displacements, and can thus be used to
obtain scanning force topography images and for making quantitative
nanoindentation measurements. For the former, the displacement
signal from the transducer is used as the input in the AFM
feedback control loop, just as its regular cantilever-beam
displacement sensor would be. Topography images are obtained
by scanning the tip across the surface while the AFM controller
adjusts the sample position so as to maintain the displacement
signal constant. Once the topography has been imaged, one
can select specific sites, and move the tip to these locations
using the AFM scanner control. Once in the selected site,
one can then use the transducer to apply load and measure
displacement while making an indentation. The resulting load-displacement
data can then be analysed using a standard nanoindentation
data analysis. The principal value of this system, compared
with conventional nanoindentation systems, is that one can
place indentations extremely precisely with respect to particular
topographical features (within a few 10's of nanometers).
The transducer and its controlling electronics and software
are made by Hysitron,
Inc.
Another feature of this machine is the ability to conduct
scratch tests. We have a second transducer (also from Hysitron)
in which a second axis of force control and displacement detection,
perpendicular to the first, is available. Thus, we can image
a surface, and make scratch tests in particular locations
with very good control of load both normal and parallel to
the sample surface.
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X-ray Microtensile
Tester
This is a special device for conducting tensile tests of
thin films on substrates in a q-q
diffractometer. The total strain in the package can be measured
using an external strain gage and the elastic strain in the
film can be measured by x-ray diffraction. Since the total
and elastic strains are known, the plastic strains can be
determined. This machine was built by Prof. Baker, André
Kretschmann, and Norbert Kühnmunch at the Max-Planck-Institut
für Metallforschung in Stuttgart. It is being modified
for use at CHESS.
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X-ray Thermal
Strain Measurement System
A new system for measuring the thermoelastic strains in thin
films on substrates is under construction. This system consists
of a heating stage inside a Be tube. The tube can be evacuated,
or filled with a desired atmosphere during the measurements.
It will be installed in a diffractometer at CHESS where x-ray
diffraction will be used to determine the strain in different
texture components during thermal cycling. We will use it
to investigate both blanket films and patterned structures
(e.g. microelectronic conductor lines).
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Other Facilities
at Cornell University
We also make use of a number of excellent multi-user facilities
available at Cornell, including equipment available at
The Cornell
Center for Materials Research (CCMR)
The Cornell
Nanofabrication Facility (CNF)
The Cornell
High Energy Synchrotron Source (CHESS)
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Facilities
at Other Institutions
We also make use of facilities at other instititutions, particularly
those available at:
The Max-Planck-Institut
für Metallforschung, Stuttgart, Germany
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