I have noticed that PMOS transistors have a higher flicker noise density than NMOS when bulk finfet technologies are involved.
Why is that?
since the mobility is more or less the same, and also the doping concentration should be (fully depleted) than why should the flicker density be different?
Run, it seems that the reason is the difference in effective masses of carriers, see e.g. physical model in IEEE Transactions on Electron Devices ( Volume: 37, Issue: 3, Mar 1990), p. 654 https://people.eecs.berkeley.edu/~hu/PUBLICATIONS/Hu_papers/Hu_JNL/HuC_JNL_173.pdf (section 3) for alpha coefficient.
All the best
Hi! The well written and brief answer written in here:
https://www.nikhef.nl/~jds/vlsi/noise/sansen.pdf
You can calculate noise density for equal NMOS and PMOS (equal width and channel length and gate area) and see the difference.
Don't know full picture, so good luck!
https://www.nikhef.nl/~jds/vlsi/noise/sansen.pdf
But in strained process the effective mobility is the same, this might be true for older generation (also the reason for the different main contributer, in PMOS not surface traps but mobility scattering).
I know the equations, but i cant figure out why there should be a difference in the constants if mobility is the same.
Thanks,
Run.
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