The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Modeling >> Semiconductor Devices >> viarations of poly resisitor
https://designers-guide.org/forum/YaBB.pl?num=1273898255

Message started by kennycs on May 14^th, 2010, 9:37pm

Title: viarations of poly resisitor
Post by kennycs on May 14^th, 2010, 9:37pm

when I simulate circuits with both mosfet and poly resistor ,I am confused how to set the corner.
As we know we can choose TT, SS, FF for mosfet ,and RMIN, RMAX, RTYP for poly resistor. However, I want to know whether the corner of poly resistor is independent with the one of mosfet ,or not ?
thanks!　

Title: Re: viarations of poly resisitor
Post by Geoffrey_Coram on May 17^th, 2010, 5:06am

I would expect the delta-L and delta-W of the poly resistors to be correlated with delta-L and delta-W of the poly gates of the MOS devices. However, I don't know whether this over/under-etch is the most important source of statistical variation. Probably the threshold voltage shift and oxide thickness variation are more important.

Title: Re: viarations of poly resisitor
Post by littlej on May 25^th, 2010, 12:06am

RES model is indepedant with mosfet and other devices.
You can use lib TT_RES/SS_RES/FF_RES.

Title: Re: viarations of poly resisitor
Post by Geoffrey_Coram on May 25^th, 2010, 6:06am

littlej - the model files may show that RES model is independent of MOS model, but I'm sure that's not completely true in actual silicon.

Title: Re: viarations of poly resisitor
Post by aLittleKnowledge on Jul 13^th, 2010, 3:57am

Variations of MOSFET gate length do correlate with variations in poly-resistor width. However, MOSFET length is also affected by sidewall oxide dimensions, and in many processes the poly-resistor is not at the same height as the gate, so the photo-effects will be different.
There is some small correlation between resistivity and VT. So far as I know there are no other correlations between these devices.

Title: Re: viarations of poly resisitor
Post by love_analog on Aug 7^th, 2010, 1:48pm

I don't think Resistor and gate will correlate that well. Typically we make the resistor wider so mitigate the delta(W) effect. most of resistor variation comes from the variation in resistivity.