Help with capacitor Layout

[chravikumar]

Hello

Which layout is best for on wafer capacitance measurement? The idea is to measure the dielectric constant of a di-electric thin film on GaAs substrate.

Regards
RK

 

[leo_o2]

Cycle shape for varactor cap structure? It will have smaller sidewall capacitance.

 

[chravikumar]

now how would that layout be ..because, google search for a varicap layout did not give any useful results...

 

[erikl]

Cycle shape

I think Leo thought of circular shape: a circle maximizes the area/perimeter ratio, so you get least error from fringe effect.

 

[Colbhaidh]

Och come on... just use a rectangular structure with large area with respect to perimeter. That is what everybody does. Use a couple of different areas to eliminate the perimeter capacitance by extrapolation. Its not that difficult.

 

[leo_o2]

Yes. Sorry for typo.

I think Leo thought of circular shape: a circle maximizes the area/perimeter ratio, so you get least error from fringe effect.