Question about "p diode" and "n diode"

[hannover90]

Question about "p diode" and "n diode"

Dear all,

I am confused between the layout of "n diode" and "p diode", please see the attachment.

In the layout of "p diode", the anode terminal is "PP" and cathode "NP", but I don't know how is about "n diode".

Should I take "NP" for the teminal anode?

Thanks for any reply in advance.

Best regards

Hannover90

- - - Updated - - -

Dear all,

I am confused between the layout of "n diode" and "p diode", please see the attachment.

In the layout of "p diode", the anode terminal is "PP" and cathode "NP", but I don't know how is about "n diode".

Should I take "NP" for the teminal anode?

Thanks for any reply in advance.

Best regards

Hannover90

Hello,

I found out the answer. The anode of diode has to be "PP" as well.

But what is the functional difference between "p diode" and "n diode"?

Hannover90

 

[dick_freebird]

The difference is in the body doping and possibly parasitic
connections, depending on the technology. Anode contact
will always be P+ and cathode N+. The body implant and
what (if any) well(s) it uses or is nested inside, you need
to dope out the drawn layers and undrawn Booleans and
draw yourself a pair of cross-sections.

 

[erikl]

Re: Question about "p diode" and "n diode"

... what is the functional difference between "p diode" and "n diode"?

In a standard CMOS process (p-substrate, n-well) the anode contact (P-Plus) of an n-diode is inevitably connected to the substrate, i.e. GND, not freely connectible.

For p-diodes, however, both nodes are freely connectible, as the n-well may have any potential between VDD and GND.

 

[hannover90]

Re: Question about "p diode" and "n diode"

Thank you very much Erik and deek_freebird for your answers. Now it is for me more clearly. Thanks!

(In my picture, I forgot to draw the nwell of "p diode".)