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Hi everyone.
Can anyone able to provide me the standard deviations of few process parameters (such as TOXe (electrical tox), Ndep (depletion conentration), Length, Width for both nmos and pmos MOSFETs) of any technology (such as b/w 16nm to 90nm) real or demo PDK. I would like to see the behavior of sigma if it is increasing or shrinking with technology nodes.
Thank you.
Thanks. Actually I am more interested in a data (figure/table) which shows Tox (sigma) Vs Technology nodes. So if anyone can refer to any paper in literature or look into the PDK files and provide sigma values of tox and few other parameters. Would really appreciate that.
So if anyone can refer to any paper in literature or look into the PDK files and provide sigma values of tox and few other parameters. Would really appreciate that.
People with access to PDK are under NDA so publishing data from it is not possible. Also I think these statistical models are not related to physical process variations but are just black box normalized statistical SPICE parameters.
Thanks for the reminder about respecting an NDA agreement. Plus here on SemiWiki you would be recognized because we only allow real names at registration time.
I have PDKs, but I dont know where to look for the standard deviation of threshold voltage of MOSFETS (and also mobility). I can access Fast, Typical and Slow corners, but when I read then they just scale VTH and TOX. But what I need is sigma(vth) for monte carlo / variation analysis.
Any help please.
I have PDKs, but I dont know where to look for the standard deviation of threshold voltage of MOSFETS (and also mobility). I can access Fast, Typical and Slow corners, but when I read then they just scale VTH and TOX. But what I need is sigma(vth) for monte carlo / variation analysis.
Any help please.
My guess is that the only one able to supply you with actual variation statistics is the PDK supplier itself (who in turn them gets these data from the actual fab, unless the two coincide).
However, in my experience many of these are reticent to give away these data even if you are under non-disclosure agreements (doesn't mean you shouldn't ask though).
Thanks all for your valuable comments for helping me and Naeem here.
However, I would still like to continue the discussion in general; based on your experiences.
Q: Should we expect that standard deviation of these process parameters (e.g. Vth0, Tox, L, W, Ndep etc.) is scaled down (i.e. shrinking) or scaling up (expanding) w.r.t to technology nodes such as 90nm towards, let say 16nm or beyond?
Expected Answer: In my opinion after literature review (where not so much one can find about it); it is expanding/ scaling up with technology node. So CMOS technology is shrinking where Variability is increasing which let sigma/std dev. of process parameters grow bigger in values (according to each parameters' mean and its std dev).
I guess you can see it in simple terms:
If you think of a transistor gate as a bullseye, and the implantation ions as arrows, the miss/hit ratio will only increase as you decrease the size of the target (everything else being equal, which I don't think is the case either).. all electrical considerations should follow from this atomistic view, given the component sizes
Q: Should we expect that standard deviation of these process parameters (e.g. Vth0, Tox, L, W, Ndep etc.) is scaled down (i.e. shrinking) or scaling up (expanding) w.r.t to technology nodes such as 90nm towards, let say 16nm or beyond?
If variability is behaving well, it is inversely proportional to square root of the gate area of a transistor; e.g. sigma = A.(W.L)^-0.5 with A called the Pelgrom constant. In the past A has scaled with technology but area has scaled faster so in general variability of minimal size transistor becomes worse. Additionally Vt and supply voltage have been scaled so that the same absolute Vt variation has more impact on circuit performance.
