RCX extraction of Power transistors

[Jagadeesh M]

Folks,
We have a situation where we have a huge POWER transistors. The
width(Width-per-finger) of the transistors is huge, by default RCX models
each finger as a single MOS device. It will collapse all the
Metal-to-contact resistors and it will connect the the center point of src/drain
metal1 to the transistor. This method of extraction is fine for a normal
application. But for huge power transistors this will be inaccurate since you
are modeling the MOS with big W(let's assume W=200um) as a single device. The
best way to model it is to break a single finger of transistor into multiple
devices along its width so that the single MOS is modelled as a distributed
device. This will be a accurate way to model this. How can acheive this using
RCX ? Let me know if you need mode details.

Rgds,
Jagi.

 

[G Vandevalk]

I understand your problem. I do not think RCX (or any other parasitic
extraction solution) will help.

I think you need to work with your modeling provider in this case.

When you break the mosfet into bits, you will bring in all sorts of modeling
effects that are not real (i.e short channel and narrow channel effects,
etc.)

What you need to do is get a model of the mosfet that models as manny of the
effects as you can.

One way would be to model each finger and add parasitics to the model as
required.
(i.e. contact, metal, etc.)

Remember that the extracted device is ideal to the RCX world.

-- G



"Jagadeesh M" <jag@heaven.com> wrote in message
news:d2e59e$k9$1@home.itg.ti.com...

Folks,
We have a situation where we have a huge POWER transistors. The
width(Width-per-finger) of the transistors is huge, by default RCX models
each finger as a single MOS device. It will collapse all the
Metal-to-contact resistors and it will connect the the center point of
src/drain
metal1 to the transistor. This method of extraction is fine for a normal
application. But for huge power transistors this will be inaccurate since
you
are modeling the MOS with big W(let's assume W=200um) as a single device.
The
best way to model it is to break a single finger of transistor into
multiple
devices along its width so that the single MOS is modelled as a
distributed
device. This will be a accurate way to model this. How can acheive this
using
RCX ? Let me know if you need mode details.

Rgds,
Jagi.