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Does u0 and vth0 viewed in simulation result reflect default constant value or the ones already considering any Layout-dependent effects in such environment: tsmc65nm, BISM4.5 model, Spectre7.2 ?

Alex Liao

After any Spectre simulation, does U0 in model parameter field mean the low-field mobility of the very original one or the one infulenced by STI/WPE or any other issues? Simply put, [url=http://postimg.org/image/l2oe8rrvh/][img]s6.postimg.org/.../url],

This image gives the equation of u0 under STI's influence. Is the u0 in ADE Result => Print Model Parameter list reflecting U0ref (may be a constant) or U0(already consider STI influence). If the case is the former (the initial constant) and then U0( influenced by STI) is invisiable to user; if it is the latter(influenced by STI) and then U0(the initial constant) is invisiable.  How about the vth0? Does the simulation result reflect final vth0 considering any layout or other issues or only give default value which is used to compute effecitive vth0 via inner equation?

 

Regards,

Alex 

Parents

  • Alex,

    The device model equations manual describes how the equations work (although it has a few omissions here and there, and sometimes you need to look at the Berkeley site to get the full model equations).

    As I said before, you wouldn't expect to see effective information in the model parameters, because these are the input model parameters. You can however get a number of useful effective parameters for each instance by doing a dc operating point and then you'll get the "Operating Point Parameters". See "spectre -h bsim4" and you'll see there's a large number of parameters, including id, ids, vth, betaeff, gm. gds and many capacitances. I don't believe there's any output of effective mobility though.

    You should see the effect of STI in the performance/behaviour of the transistors - for example, the id variation in a current mirror caused by STI (as in Bernd's presentation).

    (BTW, I'm not sure why the email subject headers are ending up as gobbledegook - I'm guessing it's something to do with either the length of the subject line or the characters in it).

    Regards,

    Andrew.

Reply

  • Alex,

    The device model equations manual describes how the equations work (although it has a few omissions here and there, and sometimes you need to look at the Berkeley site to get the full model equations).

    As I said before, you wouldn't expect to see effective information in the model parameters, because these are the input model parameters. You can however get a number of useful effective parameters for each instance by doing a dc operating point and then you'll get the "Operating Point Parameters". See "spectre -h bsim4" and you'll see there's a large number of parameters, including id, ids, vth, betaeff, gm. gds and many capacitances. I don't believe there's any output of effective mobility though.

    You should see the effect of STI in the performance/behaviour of the transistors - for example, the id variation in a current mirror caused by STI (as in Bernd's presentation).

    (BTW, I'm not sure why the email subject headers are ending up as gobbledegook - I'm guessing it's something to do with either the length of the subject line or the characters in it).

    Regards,

    Andrew.

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