... twell(green) and nplus ( brown rectangle) but the spacing between them is very less?
Are you sure that twell (the nwell) is inside the green rectangle and the p region (not nplus) for the NMOS is inside the brown rectangle?
May be the twell (the nwell) is inside the
white rectangle and the p implant region is inside the
green rectangle? The green rectangle then would fully comprise the p
- implant (the body) region for the NMOS. The brown rectangle contains the n
- implant (the "diffusion") for the NMOS itself, and the green rectangle below the red n
+ implant is the n
+ contact to the white metal1 rectangle inside it? Check your LSWindow for the layers' colors!
If so, I'd think at least in the corners of the green rectangle there should be enough space for a p
+ contact with metal1 to connect to GND. For an n+ contact within the brown rectangle is really not much space. Probably in the (other) corners, also?
Inside the (big) white nwell rectangle you need an n
+ contact (better: contacts ring) with metal1 to connect to VDD.