Section 8: Testing flash memory
Model 4200A-SCS Pulse Card (PGU and PMU) User's Manual
8-6
4200A-PMU-900-01 Rev. A December 2020
The flash projects support two methods for switching between the pulse and measure phases of the
typical flash memory test.
The first is the typical method, using a switch matrix to route the pulse or DC signals to the DUT.
Using the switch matrix is more complicated, but provides flexibility for certain tests and test
structures that use arrays. The second method uses the on-card isolation relays on both the SMUs
and the pulse cards to configure a simpler setup without the external switch matrix.
Because both the SMUs and the pulse cards have isolation relays on the cards, you can configure a
simpler setup without the external switch matrix. The advantage of the simpler setup is lower cost.
However, the switch matrix provides lower current measurement performance and the flexibility
necessary for testing arrays of test structures.
To determine the state of the device, you do a Vg-Id sweep, then perform a calculation to find the
voltage threshold (V
T
). The shift in V
T
represents a change in the amount of charge stored in the
floating gate, which indicates the state of the cell from fully programmed (
1
) to fully erased (
0
).
Figure 159: Block diagram of an example flash test setup using a switch matrix