tt, ss, ff process parameter question ....Analog circuits

[gold_kiss]

ss tt ff in cmos

Hi,
Here is a question on process parameters. I mean FF, TT, SS what is actual significace of these?
Fast Fast
Slow Slow
Typical Typical cases?

What is the relation of these ss, tt , ff cases to yield?

Is there any relation of substrate doping or concentration to process ?

Any answers that can clarify my doubts are appreciated,

Cheers,
Gold_kiss

 

[atmaca]

cmos ff ss

Which process it this ? Bipolar, CMOS, ... ??

 

[maxwellequ]

corner vth tt

This nomenclature comes, in CMOS processes, from the time where these were mainly used for digital circuits. The foundries make a characterization of their processes, analyzing the variations that it has. Then they build a model for the slowest, typical and fastest cases. If you compare these models almost all parameters have variations. One of the things that change and has a direct impact on the behavior of the transistors is the oxide thickness (tox).

Regards,

 

[tlihu]

spice process corner ss ff

Simply put it, under the same operating conditions, Vth (threshold voltages) is

|Vth,ss| > |Vth,tt| > |Vth,ff|, and thus

|Ids,ss| < |Ids,tt| < |Ids,ff|

 

[uladz55]

ff, tt, ss

Hi,

TT, FF, SS, FS, SF corner cases take all process deviations into account.

The SPICE model parameters, are listed below, usually changed for corner analysis (for N- and P-MOST).
TOXM, DXL, DXW, DELVTO, CJ, CJSW, CJGATE, CGDO, CGSO.