poly on resistor in layout?

[iamxo]

what's the role of poly on resistor in layout?
the poly is connected to ground, the resistor is p diffusion res.

 

[Fom]

It seems to be a MOS structure, not a resistor.

 

[DZC]

Is it a kind of shielding?

Added after 55 seconds:

We do use some metal to offer shielding for resistors

 

[Hughes]

A pmosfet functions as a channel resistor.

 

[jecyhale]

Maybe just for protecting the R. Or for block the noise.

 

[iamxo]

Thank you all.

 

[engrak]

i think it will be a pinch resistor .

 

[iamxo]

i think it will be a pinch resistor .

What's a pinch resistor?
Thanks.

 

[ninge]

hey guys it is new to me, pls discuss more abt this...

 

[layoutmaster]

Just with POLY on RESISTOR you can not say what it is...

As a sample, just see the posts. It was interpreted as: a MOS, a Shielding, a Pmosfet-resistors, a resistors protection, pinch-resistor...

It's just because the definition is not clear... POLY over WHICH type of resistor? That would be the key question and the starting point for a valid answer.

 

[cloudliu]

May be the poly is used for self-align, it would make the value of resistor more precise

 

[sirisha.kadiyala]

It may not be a poly on the resistor...If the poly layer is between the resistors....it means that....we you have a big resistor array(of nwell resistors), having no poly.....it voilates the poly density at that aprtcular area...
So...we used to put poly between the resistors to clean the poly density errors...and we can leave that poly as floating or we can connect that to GND.

Correct me if it's not correct

 

[sat]

Great responses! however I see people are trying to generate mental pictures, and assuming stuffs.

I'd suggest - if you could please post a picture along, people will not waste time visualizing, and higher possibility that you get a conclusive answer.

Thanks.

 

[mady79]

guess 1)Is is siprot [silicide protection] not poly what u see

guess 2)are you making capacitor or resistor

just kidding ..plzz post the pic to get answer from panel

 

[forkschgrad]

if you refer to the resistor itself, then poly is the resistive material. if it's between the resistor then it's used as as a protection from edge variation. sometimes to protect from parasitics.

 

[supreet_95]

The resistive divider being used for generating a stable referance and hence being sheided from top using poly.