area of source, area of drain, etc. if we only have the spice model

[alex2013]

Hi,
I am getting only an Hspice model from my foundry (for some reason).
Usually, when using cadence, the value of area of source, area of drain, etc will be filled automatically, but currently I have no access to cadence tools,
only using foundry-unsupported Synopsys schematic capture tools.

Any idea how do I get the values of as, ad, ps, pd, etc? or will using default values not affect the simulation result much? (there are default values hard coded in the model files)

Thanks.

 

[erikl]

These values only affect the ac & transient simulation results.

You could measure the drain & source lengths (ld & ls) - usually they are equal.

If so (ld=ls=l) :
area as = ad = w*l (w=transistor(gate)-width ; l=drain-length resp. source-length, l is perpendicular to the gate)

periphery ps = pd = w+2l (the width adjacent to the gate usually isn't counted, because this part of the capacitance is already considered by the gate capacitance).