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Modeling >> Semiconductor Devices >> SPICE MODEL
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Message started by hchanda on Nov 2^nd, 2005, 6:07pm

Title: SPICE MODEL
Post by hchanda on Nov 2^nd, 2005, 6:07pm

Hello Everyone,

How do you find NRD/NRS= number of squares for drain/source resisitance for a MOSFET?

Please let me know.

Thanks
~H

Title: Re: SPICE MODEL
Post by keble on Nov 7^th, 2005, 1:40pm

Just use this: NRD (or NRS) = Ldiff/W where Ldiff is the length of the drain/source diffusion (ie, the dimension from the poly gate edge to the edge of the diffusion) and W is the width of the transistor.
This gives an approximate answer - you could get more accurate if you need to by taking into account the sideways diffusion.
Rob