In magic, how do we connect the body of the transistor to the source? I need to avoid the body effect.

If you are using the generated cells, then enable the guard ring and connect to that. If you are drawing devices manually, the type

nsd

("nsubstratediffusion") is tap diffusion to nwell, and

psd

("psubstratepdiffusion") is tap diffusion to substrate, with corresponding contact types

nsc

and

psc

.

IMG_20240608_234408.jpg

This appears to be the Sky130 process? Your only choice then is to isolate the body by placing the transistor inside a pwell region inside a deep nwell structure. Then the substrate surrounding the nFET will not be shorted to the global substrate ground.

Will try that thanks

body of pmos is the nwell it sits in already so you just need to not put two transistors in the same nwell and you're good.

@tnt i tried your thing and it seems to work

relatedly, is there some linting/drc setting i can enable to get a warning when i do this by accident?

@Luke Harold Miles: @Mitch Bailey’s precheck test for soft connections does that.

Oh so it was actually helping me out this whole time then. I thought it just hated me personally. I guess he put those checks in there for a reason after all

@Mohammad Tahmid Hassan pmos bulk is nwell. you can physically separate nwell without using deep nwell. That’s why you don’t need deep nwell for pmos isolation - just use a different nwell.