BSIM4 Characterization
This chapter provides a theoretical background for the BSIM4 model. It is based on the model revision BSIM4.5.0, released by the University of California at Berkeley on July 29, 2005. Using the Modeling Packages is described in Chapter 1, "Using the MOS Modeling Packages."
BSIM4.5.0 covers some improvements for geometric influences, temperature and processing variations. The details are described in "New features in the BSIM4 Modeling Package, Rev. IC-CAP 2006, April 2006.
BSIM4.4.0 addresses several new issues in modeling sub micron CMOS technology and RF high-speed CMOS circuit simulation. The BSIM4.3.0 model has been improved to cover such effects as trap assisted and gate overlap tunneling, recombination currents, and flicker noise.
The BSIM4.5.0 source code, BSIM4.5.0 user manual, BSIM4.5.0 new enhancement document and testing examples can be downloaded at [1]:
http://www-device.eecs.berkeley.edu/~bsim3/bsim4_get.html
What's new inside the BSIM4 Modeling Package:
This section lists the enhancements and changes made to the Modeling Package for each revision since IC-CAP 2002. They are listed in reverse order so that the new version is on top, followed by former versions.
New features in the BSIM4 Modeling Package, Rev. IC-CAP 2006, April 2006
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Note
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The supported model is now BSIM4.5.0, released by UCB in July 2005.
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1.) General
The new effects modeled in BSIM4.5.0 are included as well as some improvements in handling the Modeling Package.
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A new mobility model, addressing Coulomb scattering as well as the mobility channel length dependence of heavily halo-doped devices |
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Improved VOFF and VFBSDOFF temperature dependency |
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Enhancements in temperature modeling using tempMod = 2: Vth(DITS) and gate tunneling models are functions of TNOM, temperature dependency of VFB is added |
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A substrate resistance model (rbodyMod = 2), scalable with NF, L, and W |
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XGW and NGCON can be specified as instance parameters |
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Threshold voltage variation is represented by a new instance parameter, DELVTO |
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Ion scattering effects during well implantation are modeled using an enhanced well-proximity effect model for parameters VTH, U0, K2 |
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Implementation of the VTH-model into the IGC-equation to allow modeling of the VBS dependence of IGC as well as IDS in the low current region |
2.) BSIM4_DC_CV_Extract
The extraction module gets some new features. Those handling improvements are described in Chapter 1, "Using the MOS Modeling Packages."
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The data display now opens a multiplot window that displays an overview of plots using any number of plots in one window (up to 100), as well as zooming in on a specific plot instead of opening a new window for each plot. |
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It is possible to arrange different types of plots and use them for extraction by means of the plot optimizer. |
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You can display different devices, different temperatures, and different plot types with this multiplot window. |
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The extraction flow is grouped into a global and a binning extraction part for a better overview. The groups can be expanded or deflated. |
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Error calculation can be made visible in the plot window. |
New features in the BSIM4 Modeling Package, Rev. IC-CAP 2006, November 2005
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Note
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The supported model is now BSIM4.4.0, released by UCB in May 2004.
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General
The new effects modeled in BSIM4.4.0 are included as well as some improvements in handling the Modeling Package. Those handling improvements are described in Chapter 1, "Using the MOS Modeling Packages."
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Shallow Trench Isolation (STI) effects |
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Enhancements in the Holistic noise modeling |
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Multilayer Gate tunneling current |
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Scalable Model has been enhanced for specific layouts using so called "Horseshoe contacts" |
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Consistency check of DC measurement data included |
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The time to load a new project has been dramatically reduced |
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Extractions for BSIM4.3.0 specific parameters have been included |
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New scheme to define de-embedding structures |
New features in the BSIM4 Modeling Package, Rev. IC-CAP 2004, November 2004
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Note
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The supported model is now BSIM4.3.0, released by UCB in May 2003.
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General
The new effects modeled in BSIM4.3.0 are included as well as some improvements in handling the Modeling Package.
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Shallow Trench Isolation (STI) effects |
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Enhancements in the Holistic noise modeling |
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Multilayer Gate tunneling current |
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Scalable Model has been enhanced for specific layouts using so called "Horseshoe contacts" |
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Consistency check of DC measurement data included |
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The time to loading a new project has been dramatically reduced |
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Extractions for BSIM4.3.0 specific parameters have been included |
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New scheme to define de-embedding structures |
New features in the BSIM4 Modeling Package, Rev. IC-CAP 2004, January 2004
1.) General
The BSIM4 Modeling Package can now generate model cards and scalable RF models for the following simulators:
Spice3 (delivered with IC-CAP)
Advanced Design System
Hspice
Spectre
All temperatures in setups and documentation are now given in [K] instead of [degree C]. Many suggestions from beta and first time users have been included into the Modeling Package.
2.) BSIM4_DC_CV_Measure
The Keithley switching matrix models K707 and K708a are supported.
The maximum compliance values can be defined together with the other measurement settings.
Three new functions are implemented to drive the BSIM4_DC_CV_Measure module from a wafer prober control macro. An example for such a control macro can be found in '.../examples /model_files/mosfet/bsim4/examples/waferprober/prober_control.mdl'
3.) BSIM4_DC_CV_Extract
A complete new extraction flow is implemented. A certain extraction group (e.g., 'Basic VTH, Mobility') can be invoked several times with different configurations.
4) BSIM4_RF_Extract
A complete new extraction flow is implemented. Please see the above noted BSIM4_DC_CV_Extract for more details.
The automatic generation of HTML files has been enhanced to include a navigation tree through all results.
New features in the BSIM4 Modeling Package, Rev. IC-CAP 2002, March 2003
The major enhancement in this update is the possibility to use the same set of measured data to extract parameters for the BSIM3 Model as well as for the BSIM4 Model.
This means, data generated by the BSIM3_DC_CV_Measure module can be imported into the BSIM4_DC_CV_Extract module and vice versa.
This feature allows the user to extract model parameters for use with the BSIM3 model as well as the BSIM4 model according to his needs, using only one set of measured data.
Moreover, the flow inside an extraction group can be specified in any desired order to get highest flexibility in adopting a specific parameter extraction to a certain process.
The automatic generation of binned model files is now supported. A new folder 'Binning' in the 'BSIM4_DC_CV_Extract' module allows the specification of binning areas as well as extended binning. Final circuits are generated for simulators supporting binned model parameters: Hspice, Spectre and ADS.
The automatic generation of HTML files has been enhanced to include a navigation tree through all results. In addition, all measured data at each temperature for each device is compared with the simulated results.
The new IC-CAP feature "Plot Optimizer" is supported through the use of an additional folder Plot Optimizer which allows the entering of devices and setups for a final fine tuning approach.
A new function is implemented to extract multiple projects in a batch mode. This can be very useful for statistical modeling, where a large number of model parameter sets have to be generated for the same type of devices but from different measured test chips. Please see the macro 'Example_Wafer_Extraction' in the BSIM4_DC_CV_Extract.mdl file.
Parameter extractions have been steadily enhanced due to user's feedback.
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