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Welcome to the Agilent EEsof EDA’s IC-CAP device modeling software Web demos. In this
demonstration, we will show you how quick and easy it is to set up an optimization using
the Plot Optimizer. We are going to use the BSIM 4.3 extraction module as an example.
There are many groups of parameters in this turnkey extraction flow.
For this demo, we will use the basic threshold voltage and mobility model parameters, which
are directly extracted from the measurement data of a large transistor. These parameters
can be extracted from the measurement data of the drain current versus the gate voltage.
And from the threshold voltage versus DPS.
We can also use the plot of GM versus VG to see how well we modeled the basic device characteristics.
The extraction of this group of parameters can be done very simply by clicking on “Single
Extraction.” That will generate the first physically extracted model parameter set.
Next, we would like to set up a local optimization routine for this group parameters.
From every IC-CAP plot, you can click Optimizer and open the Plot Optimizer. With the Plot
Optimizer open, you can start loading the target and simulated data into the input tab.
To load the input data, you can go to Optimizer and select Auto Configure and Enable. Notice how the data is automatically loaded
into the Plot Optimizer. You can do this for as many plots as you would like to use, in
order to optimize the parameters.
The Auto Configure and Enable option will automatically use the entire data set during
optimization. And the blue box covers the entire plot. If you want to optimize the parameters
of a particular data range, you can define that by creating a box on the plot and at
a global region. The blue box indicates the region to be used during the optimization.
You can add as many regions on a plot as you would like.
Notice how the Plot Optimizer automatically creates sub-regions on the input windows that
correspond to the smaller, blue boxes on the plot here. The next step is to select the
parameters. The Plot Optimizer has a drop-down list of all BSIM 4.3 parameters. You can just
click and add the parameters individual, or hold down the Shift or Control key and add a group of
parameters onto this table.
These parameters are in the Basic VTH and Mobility Extraction Group that we have preselected
and added into the list.
Once the parameters are selected, you can automatically set the min and the max values
of parameters by clicking on the Min and Max buttons here. That will narrow the range of
the parameters to a more realistic working space. The next step is to choose a design
optimizer. IC-CAP offers 13 different highly robust optimizers, each with its own error
functions and search method.
For example, the Levenberg-Marquardt uses the nonlinear search method, with the least-squares
error function. And the gradient uses the gradient search method with least-squares
error function. You can also use a combination of optimizers for best fit. In this example,
we will use the gradient optimizer to first optimize the parameter set, and use the Levenberg-Marquardt
Optimizer to further fine tune the result.
You can also set the error to “relative,” which is a percentage error value, or to “absolute,”
which is the normalized difference between the simulated and the measured data. Now you
are ready to run optimization by clicking on the Optimize button, and IC-CAP will perform
the optimization routine for you.
The first optimization using the gradient optimizer is now complete.
We now use the Levenberg-Marquardt Optimizer to further fine-tune the result. You can also
manually tune the model parameters by clicking on the tuner here. Manual tuning can sometimes
be a very effective way of optimization. And it can help you visualize how the parameters
affect your IV curves. When you are satisfied with the result, you can save the project
as a .pip file, and this can be reopened later to run the optimization. Or it can be added
into the automatic extraction. We have shown you the quick and easy way of using the Plot
Optimizer to set up and perform an automatic optimization.
IC-CAP gives you 13 different robust optimizers that allow you to effectively optimize and
fine-tune your model parameters for the best fit. That concludes this part of the demonstration.
Thank you for your attention.