erikl said:
Ion etching, however, delivers positive charges. So a p+ in nwell diode - or a PMOS - should be used (nwell connected to VDD).
ravirajdv said:
Hi erikl, Are NMOS devices not sufficient?
An n+ on p diode won't avoid the build-up of a positive voltage level possibly high enough to destroy the gate oxide.
ravirajdv said:
I have not seen anybody using the PMOS devices in addition.
Not necessarily in addition. NMOS diode only. I did! ;-)
ravirajdv said:
Reasons:
1> Since it is connected to VDD, more reverse bias leakage.
Why? I don't see a reason for this.
ravirajdv said:
Minimum allowed area is sufficient for an antenna diode.
ravirajdv said:
Do you see any other reasons, Process issues? (please throw some light)
Regards,
RDV
Hi RDV, pls. s. my reason above. Process issue: yes! The etching ions are charged positively (as ions use to be ;-) ), so obviously they tend to build up positive voltage levels rather than negative ones.
Cheers, erikl