diffusion layer in TSMC

[lucky2005]

Hi,

I am new to TSMC lib, Could some one please explain me the purpose of the diffusion layer ( is it to define the source/drain regions ?).
What i see is,
For a PMOS, there is NWELL, P-implant (for source/drain region), N-implant (for the bulk region) also there is OD(diffusion) layer from where the source and drain connections are taken out through metal.
similarly, for NMOS, there is N-implant(for source/drain region), P-implant (for the bulk region) also there is OD(diffusion) layer from where the source and drain connections are taken out through metal.

The only thing unclear here is the purpose of another layer other than the implant which they call the diffusion layer ?

Any help would be appreciated.

Thanks

 

[jerryzhao]

The diffusion layer should be named active layer.U can see the MOS's structure, you only taik about the source and drain. I think you know the gate oxide is more thinner the effect region oxide. the thin oxide on active first then manufacture ploy--then implant( P or N).

 

[qutang]

active area can make active device

 

[SplinterCell]

In the image attached here, can somebody explain what the NIMP and PIMP layers are actually for?

 

[okguy]

DIFF is the active area = diffusion of Drain and Source
NIMP = N+ implantation = N+ diffusion of NMOS drain and source
PIMP = P+ implantation = P+ diffusion of PMOS drain and source

NIMP and PIMP are for N+ and P+ masks. So, they are larger than the diffusion area.
Thick oxide and gate will block implantation, and so the MOS source and drain will be auto-aligned.