How to calculate PS, PD, AS, and AD

[yschuang]

ad as pd ps

Hello, all

I would like to know how to calculate PS, PD, AS, and AD if width, and length are known. Thanks.

 

[RealAEL]

as ad ps pd

As a starting point it may be simple for a single finger device to assume:

as (total area of source) = W x L
ps (total perimeter of source) = 2 * W + 2 * L
ad (total area of drain) = W x L
pd (total perimeter of drain) = 2 * W + 2 * L

However, it is really more complicated than that as it depends on the actual layout to be drawn. The values are for total area and total perimeter of each contact region so the number of fingers has to be taken into account somehow also. Then the W and L values should be based on the actual layout dimension in each case which may be different to the simulation parameters. Each drain and source structure may be drawn oversized compared to W and L so this oversize also has to be taken into account when calculating as, ad, ps and pd. It all depends on the layout.