fringe conductance in MOS transistors ?

[cmos_ajay]

What are fringe conductance paths in MOS transistors when you use them in a current mirror ?
Lets say you have a NMOS with (10/2) and ng = 4 .

 

[dick_freebird]

You might be talking about edge leakage, the "bird's
beak" in LOCOS or STI oxides are in effect a low
quality shunt FET with a high leakage floor and a
low subthreshold slope which can be an accuracy
detractor at very low currents (and made worse with
hot carrier injection or ionizing radiation effects).

This is omnipresent in straight stripe NMOS, whether
it is of an observable or important degree comes down
to cases (application, process technology, environment)
and it can be mitigated by layout or process means if
it's worthwhile.

I have never heard the "fringe conductance paths"
expression, though, to know if this is what's meant.