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Why do we extend Poly Over the Diffusion in Layout #thesiliconvlsi
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May 11, 2025
Why do we extend Poly Over the Diffusion in Layout #thesiliconvlsi
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0:01
Hello friends today I am going to
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discuss about why we extend the pulley
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over the diffusion
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I hope you know the CMOS verification
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process in that we are using a piece of
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after that annual fabrication is
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there after that poly will fabricate it
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after that source and drain implant will
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be there so here second question might
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come like why we are using poly instead
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of metal gate so so for that I have a
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different video you can watch later so
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first we will concentration on this poly
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extension if you see here
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clearly be here this is poly extension
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is there why can't we use like this way
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let me draw the diffusion
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let me draw the polling why we can not
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do like this way why we there is
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extensions needed so as I told you like
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first poly will fabricate after that
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with the iron implantation source and
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drain will fabricate it so for that poly
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will fabricate in fabrication process
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the whatever fabricated layer is there
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it is not exactly as the drawn with so
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here if you see I draw pulley exactly on
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the edge of the diffusion so after
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fabrication there might be chances to
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short between showers and drain let me
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show you how it will show let's assume
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this is source and drain so when pavoli
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will be fabricated it will be like this
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way
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like this
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it will not exactly fabricated as here
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so there might be chances between short
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between source and drain to avoid that
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we are extending the pulley over the
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diffusion so the main definition why we
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are using why we extend pole over the
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diffusion is we extend poorly from the
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diffusion to avoid the short circuit
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between the source and ring
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during the fabrication process so this
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is the main keyword what I am going to
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explain you is this short circuit
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between source and Trend so the main
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answer for this question is to avoid the
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short circuit short circuit between
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source and drain we are using pulley
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extension
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I hope you get the answer thank you so
2:20
much for watching my video
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