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questions about a sturcture to avoid antenna effect in

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Junior Member level 3
Jul 25, 2005
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In the layout, every node, there are two diodes connected in series to avoid antenna, who can tell me how it works, thanks

Yes if u place the diodes wt happens is u can avoid antenna effect

the reason is simple the diodes are made from diffusion , but the poly is deposited onto wafer bfore the diffusion are implanted into the wafer.Hence the diode doesn't exist at the time the poly is fabricated on the wafer

And one more explaination is when the more charges are deposited on the metal lines which are running parallely over a long distance..If it touches the gate oxide the gate oxide will break so we will try to put a diodes in between them so that we can reduce it
How means it depends upon the max diode rating if it exceeds then only it gets discharges
We will place the layout of that which is nothng but metal and the contact...

Or we can use jogs to reduce this antenna affect

Don't forget to push help button
Bye take care

Using metal jump is another way to avoid antenna effect.
Example below:

••••••••••••••••••••••••••••••short metal 3
••••••••••••••••••short metal 2•••••••••••long metal 2
•••••••short metal1••••••••••••••••••••••••••••••••••long metal1
• • poly

when the voltage is very large ,the diode will reverse turn on. it discharge. so the input mos wouldn't be breakdown by the high voltage

both of antenna diodes and using the metal jump can solve this problem.

antenna diodes is convinient when you are running the APR.

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