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Difference between n/p –select and n/p - active layers in CMOS layout techniques.

RAO VINAY
RAO VINAY over 13 years ago

Hi,
What is the significance of using n/p select layers along with n/p active layers to make a CMOS active device? Why we need to draw extra n/p select layers though we can distinguish P and N regions just by using P/N active regions?



Regards,
Vinay Rao.

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  • Andrew Beckett
    Andrew Beckett over 13 years ago

    Vinay,

    Your question is almost certainly specific to the particular foundry/process design kit you're using, rather than being general to all CMOS technologies. I don't know what you mean by "n/p select layers" so can only assume that it's something in the particular technology you're using. In most technologies you either draw a diffusion (or "active") region and then draw an implant layer to make it N or P (or you draw N-diffusion or P-diffusion).

    Andrew.

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