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6 Memory
6.9 NandFlash2 Retention(WrittenCell): NAND flash memory cell Data
retention test after Write (A.01.20)
[Supported Analyzer]
B1500A
[Description]
Performs the data retention test for the NAND type flash memory cell after the write operation, and plots the
accumulated time vs threshold voltage characteristics. The test is performed as follows.
1. Applies the write pulse.
2. Measures the Id-Vg characteristics, and extracts the threshold voltage (Vth).
3. If the accumulated time is 100 seconds or less:
Performs the drain current sampling measurement, 10 seconds in 1 second step.
After the sampling measurement, measures the Id-Vg characteristics and extracts Vth.
4. If the accumulated time is more than 100 seconds:
Performs the drain current sampling measurement, 100 seconds in 10 seconds step.
After the sampling measurement, measures the Id-Vg characteristics and extracts Vth.
5. Repeats 3 or 4 until that the accumulated time overs the specified TotalRetentionTime.
The available TotalRetentionTime value is 10 to 10000 seconds.
[Device Under Test]
NAND-type flash memory cell
Connect the Control Gate to the ASU Output, and the Drain to a SMU.
Open the Floating Gate, and connect the other terminals to a SMU.
[Required Modules and Accessories]
Agilent 81110A pulse generator (2-output, PGU1 and PGU2) 1 unit
HRSMU/ASU 1 set
ASU connections: Output: Control Gate, SMU: HRSMU, AUX: PGU1
Setting of ASU I/O Path, ASU tab, Configuration window: AUX
[Device Parameters]
Lg: Gate length
Wg: Gate width
Temp: Temperature
IdMax: Drain current compliance
[Test Parameters]
Gate: SMU connected to Gate terminal, primary sweep voltage output
Drain: SMU connected to Drain terminal, constant voltage output
Source: SMU connected to Source and Substrate terminals, constant voltage output
VgStart: Sweep start voltage for Gate terminal
VgStop: Sweep stop voltage for Gate terminal
VgStep: Sweep step voltage for Gate terminal
Vd: Drain voltage
Id@Vth: Drain current to decide the Vth
IntegTime: Integration time
PulsePeriod: Write pulse period
PulseDelay: Write pulse delay
PulseWidth: Write pulse width
Vwrite: Write pulse output level
Agilent EasyEXPERT Application Library Reference, Edition 8
6-21