About Alignments
When you put a new sample in your chamber or move to a new sample that’s already in your chamber, you must do an elastic peak alignment. An elastic
peak alignment ensures that the distance between the sample and the analyzer
(for an Auger elastic peak alignment and SIMS) or the sample and the X-ray source
(for XPS) that you’re using is optimal. Part of the process of acquiring an alignment is done
manually, while part of it is done using the software.
An alignment is the only acquisition type for which the data is not averaged.
Every sweep is a fresh scan of the sample. Therefore, you cannot “continue” an alignment.
AES Alignments
There are two distinct uses of the AES alignment procedure. The first use is
the AES elastic peak alignment (for when you put a new sample in your chamber
or move to a new sample that’s already in your chamber). The AES elastic peak alignment is the most
commonly used type of AES alignment. In fact, AES is the only technique for which an
elastic peak can be acquired.
The second reason for acquiring an AES alignment is to monitor the presence of
elements on the surface of your sample (for example, carbon). This second use
is referred to as simply the “AES alignment routine.” You will perform the AES alignment routine to sweep over a specific energy
range to determine the correct multiplier voltage before acquiring a survey,
depth profile, or multiplex when you are using an analog multiplier supply (such
as the model 20-075).
For an AES Elastic Peak alignment, you align the sample to the focal point of
the analyzer by setting the software acquisition parameters in the Alignment
Settings dialog box while physically moving the sample until the distance is
correct (as indicated by the colored vertical line in the AugerScan document window).
When acquiring data, you must determine if you are using an analog multiplier
supply (such as the 20-075) or a digital multiplier supply (such as the 32-100)
multiplier supply because this determines the procedures you follow for
acquiring data. For example, when you use an analog multiplier supply, you need to
acquire the AES alignment routine before performing all acquisition types. When
you use a digital multiplier supply you will use the AES elastic peak
alignment routine while you will seldom use the AES alignment routine. The procedures
for acquiring the data will guide you through these details.
You can differentiate AES alignments during acquisition to get a better
picture of the peak characteristics. To do this, select the Differentiate command after the alignment is started. To revert back to peak N(E) data,
select the Revert to Raw command.
XPS Alignments
For XPS, do an AES elastic peak alignment first, then use an XPS alignment to
optimize signal by moving the X-ray source position.
SIMS Alignments
Before you acquire a SIMS alignment, you must first acquire an AES elastic
peak alignment. Even though you may not acquire AES data, the elastic peak
alignment ensures that the ion gun is properly aligned with respect to the sample.
Remember that SIMS is a destructive technique so that the sample is changing as
you sputter it away. Typically, you will do a SIMS alignment on the edge of
your sample and then simply move the stage’s X axis to the area of the sample that you want to acquire. (If you are
moving only the X-axis, you do not need to acquire another AES alignment. Or, you
can do an alignment on one sample, then move to another sample, do an AES
alignment, and acquire your data.) When you are acquiring a SIMS alignment, you may
change the Acceleration voltage, Retard voltage, Ion voltage, and Focus
voltage settings in real time. This lets you see the effect that changes to these
settings have on the data that is acquired.
Additionally, a SIMS Positional Alignment can also be used for optimizing your
SIMS acquisitions. Click here for more information.
To get information on acquiring alignments for a specific technique, click on
one of the items below:
AES Elastic Peak Alignments
XPS Alignments
SIMS Alignments