Sweep Waveforms - Keithley SourceMeter 2400 User Manual

6-12 Source-Measure Concepts

Sweep waveforms

There are four basic sweep types to select from: linear staircase, logarithmic staircase,
custom, and source memory. Three of the sweeps are shown in
case sweep goes from the start level to the stop level in equal linear steps. The logarithmic
staircase sweep is similar except it is done on a log scale with a specified number of steps
per decade. The custom sweep lets you construct your own sweep by specifying the num-
ber of measure points and the source level at each point. For a source memory sweep, up
to 100 setup configurations can be saved in memory. When the sweep is performed, the
setup at each memory point is recalled. See
operation.
An SDM cycle is performed on each step (or point) of the sweep. Thus, one measurement
will be performed at each step (level). The time spent at each step (level) depends on how
the SDM cycle is configured (i.e., source delay, measure speed) and the trigger delay (if
used).
NOTE
When using the Pulse Mode of the Model 2430 to perform sweeps, source delay
is not used. Pulse Mode operation is covered in
for information on Pulse Mode sweeps.
Typical applications for staircase sweeps include: I-V curves for two- and three-terminal
semiconductor devices, characterization of leakage versus voltage, and semiconductor
breakdown. Pulse sweeps are used in applications where thermal response is measured or
where sustained power levels can damage the external device under test (DUT). Source
memory sweeps are used in applications where multiple source-measure functions and/or
math expressions are required.
The custom sweep can be used to configure a pulse sweep with a 50% duty cycle. For
example, a 1V pulse sweep can be configured by programming the odd numbered points
for 1V and the even numbered points for 0V. When the sweep is run, the output will alter-
nate between 1V and 0V.
After a sweep is run, the data is stored in the sweep buffer. This data can be accessed from
the front panel or sent to a computer (remote operation) for evaluation (plotting). Statisti-
cal information on readings stored in the buffer are also available from the front panel.
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2400 Series SourceMeter User's Manual
Figure 6-3. The linear stair-
Section 10 for more details on sweep
Section 5. Also, see Section 10