Matching layout techniques

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fixrouter4400

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matching layout

Hi there I just want to know more matching layout techniques. Is it acceptable just to add a dummy polysilicon layer side by side on a matching transistors and connect it to power or ground? Instead of adding an extra dummy transistors side by side?
 

I don't think so, the matching rule actually requires the surrounding environment to be the same for the matching paires, in the processing, the diffusion density or metal/poly density around the matching pair will actually affect the matching device themselves, without dummy diffusions, it is hard to guarantee the source/drain diffusion of the matching pair are doped identical.
so unless you can leave ~2u white space (90nm process), dummy transistors(not dummy poly only) are required.
 

thank you for the reply can u send me a sample layout.
tnx
 

this am example of matching layout with circuit, in the circuit MNT1 shall be matched with MNT0, also MNINP should be matched with MNINM, so that you can see from layout how the matching is done

1. for MNT0/MNT1 matching, we leave enough space between, so a dummy is not necessary
2. for MNINP and MNINM matching a dummy is inserted on both left and right side of the device stripe as you can see.
 

You can put dummy transistors side by side using the same W but lesser L.
for example if you have a transistor with W=8 and L=4 you can put dummy transistors with W=8 and L=1 as long as W remains. This technique can help you save space as well
 

thanks guys for the help...really appreciated..
 

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