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Strain-Engineered MOSFETs
7.1 TCAD Calibration
TCAD acts as a bridge between the process and the device engineer. TCAD
calibration refers to the process of selecting appropriate models and adjusting the model parameters so that the response of the physical model can
predict the measured values. It may be noted that even the measured data
being used for calibration (e.g., SIMS or I-V) may have experimental errors
that cannot be controlled or estimated. If the goal is to predict a new technology that is being developed and is changing, TCAD calibration will be
essentially a dynamic process. TCAD has technical limitations that must be
addressed to achieve the full potential of TCAD in semiconductor technology development and manufacturing. Aside from the difficulties intrinsic to
TCAD calibration, such as measurement errors and physical understanding,
some problems arise from the way one develops and uses the models. As
such, for industrial usage of TCAD for predictive process and device simulation, special care needs to be taken. The knowledge of the technical limitations of TCAD is crucial to set realistic goals and expectations from TCAD.
The major technical limitation of TCAD, such as accuracy and predictability,
must be addressed by a proper calibration of process and device models.
During simulator (either process or device) development physical models
are implemented in TCAD tools. For advanced device simulators, special
emphasis on emerging topics, like quantum mechanical confinement, tunneling, and discrete dopant effects, is needed. For example, limitations of
drift diffusion and hydrodynamic models in nanoscale device simulation
are well known.
The critical issues that require special attention are physical model calibration, selection of effective physical models, numerical aspects, grid generation, and so on. The properly characterised process and device models can be
effectively applied to develop fabrication process technology that can significantly reduce the development cycle time and cost. The general philosophy
and the step-by-step procedure of numerical model calibration for predictive
application of TCAD in technology and device design have been presented
in [1]. In this approach, the entire product development cycle is divided into
three phases: the generation of the initial process recipe, the optimisation
of the process technology, and the evaluation of process manufacturability.
Although currently the device simulation has a relatively strong basis, the
new phenomena are of greater importance in the deep submicron devices,
and the device performance predictions are inevitably linked to process
TCAD. The role of benchmark standards and calibration testers in verifying
the fundamental accuracy of the device simulators themselves is a challenge
for the research community.
The elusive goal of TCAD is to achieve predictability of the final device characteristics, based on actual process conditions rather than idealised processes.
Sensitivity studies must be included to isolate the important parameters.
Strain-Engineered MOSFETs
7.1 TCAD Calibration
TCAD acts as a bridge between the process and the device engineer. TCAD
calibration refers to the process of selecting appropriate models and adjusting the model parameters so that the response of the physical model can
predict the measured values. It may be noted that even the measured data
being used for calibration (e.g., SIMS or I-V) may have experimental errors
that cannot be controlled or estimated. If the goal is to predict a new technology that is being developed and is changing, TCAD calibration will be
essentially a dynamic process. TCAD has technical limitations that must be
addressed to achieve the full potential of TCAD in semiconductor technology development and manufacturing. Aside from the difficulties intrinsic to
TCAD calibration, such as measurement errors and physical understanding,
some problems arise from the way one develops and uses the models. As
such, for industrial usage of TCAD for predictive process and device simulation, special care needs to be taken. The knowledge of the technical limitations of TCAD is crucial to set realistic goals and expectations from TCAD.
The major technical limitation of TCAD, such as accuracy and predictability,
must be addressed by a proper calibration of process and device models.
During simulator (either process or device) development physical models
are implemented in TCAD tools. For advanced device simulators, special
emphasis on emerging topics, like quantum mechanical confinement, tunneling, and discrete dopant effects, is needed. For example, limitations of
drift diffusion and hydrodynamic models in nanoscale device simulation
are well known.
The critical issues that require special attention are physical model calibration, selection of effective physical models, numerical aspects, grid generation, and so on. The properly characterised process and device models can be
effectively applied to develop fabrication process technology that can significantly reduce the development cycle time and cost. The general philosophy
and the step-by-step procedure of numerical model calibration for predictive
application of TCAD in technology and device design have been presented
in [1]. In this approach, the entire product development cycle is divided into
three phases: the generation of the initial process recipe, the optimisation
of the process technology, and the evaluation of process manufacturability.
Although currently the device simulation has a relatively strong basis, the
new phenomena are of greater importance in the deep submicron devices,
and the device performance predictions are inevitably linked to process
TCAD. The role of benchmark standards and calibration testers in verifying
the fundamental accuracy of the device simulators themselves is a challenge
for the research community.
The elusive goal of TCAD is to achieve predictability of the final device characteristics, based on actual process conditions rather than idealised processes.
Sensitivity studies must be included to isolate the important parameters.