The Scienta ESCA 300 is generally regarded as one
of the best XPS instruments in operation today. A combination of
design factors permit data to be obtained from samples rapidly without
sacrificing energy resolution. A basic summary of the instrument
is provided below.
X-ray source: Monochromatic
Al Kα x-rays generated from a rotating anode which can operate
at power levels of up to 7.5 kW. The monochromator consists of seven
crystals mounted on three Rowland circles. The x-ray spot is a line
>5mm long and >1mm wide.
Energy analyzer: High
resolution 300 mm mean radius hemispherical electrostatic analyzer
designed for high throughput with small solid angle acceptance for
enhanced angle resolved XPS capabilities.
Detector: Multi channel
microchannel plate-CCD camera combination.
Non-line-of sight monochomatic low energy electron flood gun
Sample stage and manipulation:
5 axis computer controlled precision manipulator. Sample heating
to >600°C and sample cooling to -100°C.
Sample analyses: Multiple
sample analysis and unattended operation are available by programming
the sample positions and analysis sequences. This can include full
sets of angle resolved analyses. Sputter depth profiling is also
possible. After suitable training, investigators may operate the
instrument and analyze their samples, or, if more convenient, the
samples can be sent to Lehigh for analysis.
Analyzed area: The nominal analyzed
area is rectangular with approximate
dimensions of 4 mm x 0.2 mm for a total area of about 0.8 mm². The
size of the analyzed area can be adjusted electronically and mechanically.
The minimum practical area for routine sample analysis is about
0.5 mm x 0.1 mm.
In situ sample preparation:
The sample chamber and/or attached chambers provide the ability
to heat specimens to >1000°C without the use of electron bombardment,
expose surfaces to various vacuum compatible reactant gases, deposit
thin films from a precision Knudsen cell and monitor the thickness
with a crystal monitor, monitor the vacuum with an RGA, fracture
brittle samples in situ, sputter clean surfaces, and scrape surfaces
in UHV. The sample entry chamber, which can have base pressures
in the low 10-8 torr range, can be used to carry out experiments
at temperatures >400°C at pressures ranging from 10-8 to 700
Sample types: Virtually
any material with outgassing rates that allow the pumps to maintain
pressures of 10-7 torr or lower can be analyzed. In the past, this
has included a number of unusual materials including fabrics, skin,
Data analysis: DOS based
or Windows based software is available free-of-charge to carry out
the data analysis. Either program can be used to export the data
as text files that can be imported into other data analysis software.
Data can be taken at Lehigh and e-mailed to the user if desired.
Scope of effort: Most
work is done on a sample by sample basis at an hourly or daily rate.
Small projects that may take a few days to a few weeks of instrument
time are also welcomed. The cost of this approach is taken on a
case by case basis. Within limits, it may be possible to accommodate
modifications to the instrument which will allow specific experiments
to be carried out in situ.
Inquiries regarding technical aspects of the instrument,
availability of instrument time and the extent to which changes
can be made to accommodate special experimental needs should be
Dr. Henry Luftman