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Simulators >> Circuit Simulators >> are Spice models more reliable than spectre ones ??
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Message started by Mayank on Jan 11^th, 2010, 2:59am

Title: are Spice models more reliable than spectre ones ??
Post by Mayank on Jan 11^th, 2010, 2:59am

Hii MOSFET Modelling gurus,

My Dilemma :-- I have been given to understand that modelling of a process technology depends on the MOSFET model ( BSIM4 or BSIM ) it uses & the way it defines all the parameters in that MOSFET model....But some guys keep telling me that spice models are better than spectre models...and some believe that spectre models are better than eldo models...
My Beliefs :--- I though that spectre / spice models are same description of a basic MOSFET model ( say BSIM4 for eg ) and are just written in simulator specific language...& so they should provide same accuracy.
And by accuracy i mean CAD vs Si Matching.
In Short, What i wanna ask is --- Are the process models of same technology simulator specific as far as accuracy is concerned ?

--
Mayank.

Title: Re: are Spice models more reliable than spectre ones ??
Post by ACWWong on Jan 11^th, 2010, 5:03am

Hi Mayank,

My belief is largely the same as your belief... the BSIM/MOSFETLVLx/PSP/EKV etc. is the model and the different different simulators use this same base information. The model type specifies the device equations to solve independent of simulator/solver
Now how the simulator solves these equations (and in some case which it solves), and then the circuit equations, allows for differences between ELDO,SPICE,SPECTRE etc....

Cheers
aw

Title: Re: are Spice models more reliable than spectre ones ??
Post by sheldon on Jan 11^th, 2010, 8:19pm

Mayank,

It is not really clear what you are asking for. The big picture
is that everybody in the industry worries about models and
modeling, that is, why there is the Compact Modeling Council.
You might this site helpful,

http://www.geia.org/Meeting-Minutes-and-Presentations-from-2007-to-Present

As a result of the CMC, the models themselves should be pretty
consistent, however, as AC points out the there may be some
differences between solvers. The other place where there may
be gray is when there are no defined standard models.

Best Regards,

Sheldon

Title: Re: are Spice models more reliable than spectre ones ??
Post by Riad KACED on Jan 12^th, 2010, 4:04pm

Hi Mayank,

BSIM3, BSIM4 and PSP are industry standards that have been approved by The CMC as explained earlier. Your foundry should provide you with figures that compare Simulation results against Si measurements.
What usually happens is that the foundry extracts the models for a given simulator and then derives parameters for other simulators using some translation tools.

Over my past experiences, I have used both Eldo and Spectre for production chips and did not see any major mismatch.

The rule of thumb is to stick at the Golden Simulator as defined by your foundry.

Cheers,
Riad.