Variability of MOSFET Series Resistance Extracted from Individual Devices: Is Direct Variability Measurement Possible?

Source-to-drain series resistance (R
SD
) of a large number of identically designed MOSFETs was extracted using a recently proposed single-device method. By examining statistical correlations with other device parameters, it was confirmed that variability of the extracted R
SD
values does not correspond to real series resistance variability, but is mainly caused by some non- R
SD
variability sources. This suggests that, for the single-device method to work, non- R
SD
variability needs to be reduced by averaging multiple devices, or using wide channel devices.