SECTION1
Getting
Started
occurs during each programmed step
or
point of the
sweep. Each measurement in the sweep
is
stored
in
the
sweep buffer.
Sweep
Types
There are six basic sweep waveforms to select from
and
are shown in Figure
1-4.
Source levels, delay times
and
measurement points of a sweep waveform are pro-
grammed
by
the user. Except for the fixed level sweep,
each step (or level) of a sweep waveform consists of a sin-
gle SDM
cycle. Thus, one measurement will
be
per-
formed
at
each step (level)
and
stored
in
the sweep
buffer.
Typical applications for staircase sweeps include;
1-V
curves for
2-
and
3-terminal semiconductor devices,
characterization of leakage vs. voltage,
and
semiconduc-
tor breakdown. Pulse sweeps are used in similar applica-
tions where thermal response
is
measured
or
where sus-
tained power levels can damage the external device un-
der
test. The fixed level sweep allows the
unit
to function
as a data logger with a time stamp. The time stamp
is
gj gj
I
Delay
I~
I
Delay
I~
I
L
1
i----''-'-.....:...-....:....;:.......;--
eve
Bias
Bias
Fixed
Level
Linear
Stair
Logarithmic
Stair
Figure
1-4.
Sweep
Wavefonns
+
available for all sweep types allowing time-dependent ef-
fects to be measured.
In
addition to the built-in sweeps, the user can append
different sweep types together (sweep append)
or
mod-
ify
an
existing sweep point-by-point (sweep modify) to
develop a custom waveform.
Sweep
Buffer
After a sweep
is
run, the data for
up
to
1000
measurement
points
is
stored
in
the sweep buffer. This data can be ac-
cessed from the front panel, or, over the
IEEE-488
bus,
sent to a computer for evaluation (i.e. plotting).
Figure
1-5
shows
an
example of a sweep. The table shows
the type of data that
is
stored in the sweep buffer for
every measurement point. The delay column
in
the table
lists the delay period programmed
by
the user for each
step of this sweep. Notice that a different delay was pro-
grammed for the fifth step of this modified sweep.
Bias
Pulse
~Stop
Bias
Linear
Stair Pulse
Logarithmic
Stair Pulse
To Next Page
Loading...
