Raw PFET Data is very noisy

google / skywater-pdk-sky130-raw-data

Raw data collected about the SKY130 process technology.

https://sky130-pdk.rtfd.io

Apache License 2.0

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Raw PFET Data is very noisy #17

Open SpaceDreams opened 2 years ago

SpaceDreams commented 2 years ago

Expected Behavior

For comparison, refer to data collected by Infineon for PSP modeling. Key points:

Their ID looks noise free down to several tens of pA, see p. 12 (instead of 200nA)
Their VG step size is also 50mV, so should be OK for us as well

Actual Behavior

From the "sky130_fd_pr__pfet_01v8_w1u_l0p5u_m1(8405_11_10_IDVG)" data we get:

Steps to Reproduce the Problem

Check out my google colab jupyter notebook here

Specifications

Tested: sky130_fd_pr__pfet_01v8_w1u_l0p5u_m1(8405_9_8_IDVG).mdm
Tested: sky130_fd_pr__pfet_01v8_w1u_l0p5u_m1(8405_11_10_IDVG).mdm'
Platform: Google Colab

metroid120 commented 2 years ago

Having worked on several technologies, I can confirm that the data is quite sparse and noisy. The only fix I can think of is to re-measure the data...

akinakturk commented 2 years ago

This data needs to be retaken using a different die. This may be due to remnants of polyimide left on the pad. I believe this data looked fine when we looked at the data in its entirety. It is sometimes easy to miss noisy data corresponding to a low bias. I am making a list of devices that we can measure using a different setup and a different die.

Additionally, the test chip devices have labels not always easy to decipher. For example this device was not labeled sky130_fd_pr__pfet_01v8_w1u_l0p5u. We had to guess the correct nomenclature. Since multiple labels for the same device are potentially used, it is not always clear what the device should be called.

mithro commented 2 years ago

FYI - Now the Pad documentation spreadsheet is publically available @ https://bit.ly/sky130-testtile-edit we have been trying to improve naming column.