STI Stress Effect Modeling in MOS Devices
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Solution Overview
Problem
Current STI stress effect modeling methods, such as the BSIM4 model, do not accurately account for the influence of temperature on MOS device performance, leading to inaccurate extracted model parameters, particularly at low temperatures.
Innovation Solution
Introduce temperature parameters into the BSIM4 model to establish a function describing how STI stress effects change with temperature, extract model parameters at normal temperature, and further extract fitting parameters at non-normal temperatures to refine the model parameters, specifically considering the impact of source-end and drain-end active region widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the BSIM4 model is used for STI stress effect modeling, then the model can be implemented with standard parameters, but the temperature influence on STI stress effect is not accurately considered leading to imprecise model parameters
Solution Approach 1:
The patent modifies the BSIM4 model by introducing temperature-dependent parameters (kual and kubl) that multiply the stress-related parameters (ua and ub). This parameter change approach allows the model to account for temperature influences on STI stress effects while maintaining the overall BSIM4 model structure, thereby improving measurement precision without excessive complexity increase
Solution Approach 2:
The patent segments the stress effect modeling into temperature-independent base parameters (ua, ub) and temperature-dependent scaling factors (kual, kubl). This segmentation allows independent extraction and optimization of each parameter set, improving overall model precision while managing complexity through modular parameter handling
2Reliability
If temperature parameters are introduced into the BSIM4 model to describe STI stress effect changes, then the accuracy of device performance prediction is improved, but the model complexity increases
Solution Approach 1:
The patent introduces temperature-dependent parameters kual and kubl that scale the stress parameters ua and ub based on temperature deviations from a reference temperature. This parameter change approach enables accurate device performance prediction across different temperatures while maintaining a relatively simple model structure by using multiplicative scaling rather than completely redesigning the model
Solution Approach 2:
The patent makes the model dynamic by allowing parameters to vary with temperature through the kual and kubl factors. This dynamic approach improves reliability for different operating conditions while managing complexity by using simple linear temperature scaling rather than complex temperature-dependent functions
Data Source
AI summary
The invention discloses an STI stress effect modeling method and device of an MOS device, and belongs to the technical field of parameter extraction modeling of devices. The method comprises the following steps: introducing the influence of temperature parameters on the STI stress effect of the MOS device, so as to form a function showing that the STI stress effect of the MOS device changes along with the temperature parameters; extracting the model parameter Model1 of the MOS device at normal temperature; on the basis of the Model1, extracting the parameter Model2 that the STI stress affects the properties of the MOS device at normal temperature; and on the basis of the Model2, extracting fitting parameters of the MOS device in the function so as to acquire final model parameters. The device comprises a first module, a second module, a third module and a fourth module. By establishing the function showing that the STI stress effect of the MOS device changes along with the temperature parameters, the influence of the temperature on the STI stress effect of the MOS device can be accurately described, so that the extracted model parameters are more accurate and reliable.