Isolation using DNWELL

[Fady Atef]

dnwell layout

hello all

I need to know the different isolation tech that can be done using the DNWELL , like Trench Isolation between RF chanel, or DNWELL under each RF channel .

which is better?and why?

thanks, and have nice day

 

[jecyhale]

dnwell

hello all

I need to know the different isolation tech that can be done using the DNWELL , like Trench Isolation between RF chanel, or DNWELL under each RF channel .

which is better?and why?

thanks, and have nice day

I think DNWELL may the best so far, because it can generate a isolated P-sub.

And it looks like a island. So all frequeny domain noise will be isolated well.

 

[Fady Atef]

n+ od

Thanks,

 

[ninge]

deep nwell isolation

Me also feel DNWELL is Better...

 

[Teddy]

noise isolation nbl

In general you hav access to shallow trench, deep trench , deep Nwell and Nwell and P+ N+ diffs.
The deeper the barrier the better isolation. In fact the best would be if you would have EPI process with high resistive substrate. Then your Deep Nwell or deep trench would cut out the island on silicon so you would truly have a "separate" substrate for the given device. Since most of CMOS technologies do not provide high resistive substrate (quite often EPI and subst are about the same) those isolation techniques gives you some but not ideal isolation.
Deep Nwell to be really effective needs to have minimnm width == to EPI thickness.
To summarize - Deep trench #1, Deep Nwell #2 shallow trench #3

 

[Fady Atef]

isolated from the substrate by epi process

yes I hav access to shallow trench, deep trench , deep Nwell and Nwell and P+ N+ diffs


At first i make the isolation using deep trench (n+, OD, Nwell, and deep Nwell ), then more than one adv. me to use Deep nwell as it make it as island,

so which is better in isolation

Added after 14 minutes:

Deep Nwell to be really effective needs to have minimnm width == to EPI thickness.
To summarize - Deep trench #1, Deep Nwell #2 shallow trench #3

WHAT did u meen ?

 

[leo_o2]

In my opinion, Deep Nw + NBL (N+ buried layer) is the best for isolation.