ACWWong
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Hi Berti,
Yes the RF device layer is typically just a CAD layer, although it can be used by the extraction tools (i.e. not to double count fixed pcell metalisation during RCX) or metal fill process (for metal fill exlusion purposes) or physical verification.
I agree the DC parameters should be very similar for both the RF and normal device, I've never seen an RF device which is not just a fixed layout. Having said that, its always good to look at the model card/equivalent circuit for the device. There are two common ways the RF devices are made: 1) normal FET model with added parasitics (like Rg, Rd, Rs, Rb, etc.) 2) complete extraction, normally BSIM. In this case you'll see that the RF devices have a different BSIM level to the standard devices. This could lead to discrepancies in DC behaviour, but one would hope these discrepancies would be small.
Cheers
aw
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