I have a question on the body effect of MOS transistor. In particular, how does the body effect in PMOS be eliminated (by connecting bulk to source together) while this similar technique doesn't do the same to NMOS?
The answer to this question is given by:http://www.onmyphd.com/?p=body.effect It is saying that PMOS is fabricated as N-well such that such PMOS are physically seperate from each other (seperate from other well) so that you can connect bulk to source to each one of them individually. On the other hand, NMOS shares a common substrate, so if you were to connect the source and bulk, you will have to do so for all NMOS.
However, I still don't see the reason doing this in NMOS will cause any problems at all.