Janghoo Lee

Hi everyone,

I’m Senior of Department of Electronics and Display engineering, Hoseo university.

I’m measuring the I-V curve of TFT fabricated by our fab, using 4200A-SCS.

The leakege current of TFT when TFT turns off doesn’t lower than 0.xxpA. It seems like limited by SMU’s.

I have two SMUs.
SMU1 is connected with PA.
SMU2 is connected with nothing.

In the manual, using PA give more measurement resolution if i undersatnd well.

I tested n-channel MOSFET(VNO104) and TFT for find the limit.
There are graphs.

Gate : SMU1(PA FORCE) or SMU2(FORCE)
Drain : SMU2(FORCE) or SMU1(PA FORCE)
Source : GND unit(FORCE)

If i use SMU1 to measure Ids, it can measure almost fA but that looks very strange. Like stairs.

If i use SMU2, it is higer than SMU1.
But the graph is linear and fine to see.

I’m looking for find the solution for this problem.
How can i solve this?



Thank you
From Janghoo Lee.