Hi quanble,
Yes you are right, but still NMOS is preferred over PMOS as the parasitic channel resistance of NMOS is less than it for the PMOS which makes the time constant of NMOS is smaller that it for the PMOS & hence you can get better performance
Sorry for mixing it up .
best regards,
Rania
Added after 4 minutes:
Hi,
To get also smaller parasitic resistance for the decoupling cap, the length shouldn't be too small, which increase the gate resistance and also not to large
There is a perfect value for it dependent on the process used
best regards,
Rania