SOI Kink Current Calculation via Impact Ionization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for calculating kink current in SOI devices are complex and unsuitable for circuit simulation due to reliance on empirical parameters and poor fitting performance at multiple gate voltages.
Innovation Solution
A method that calculates kink current by obtaining impact ionization and parasitic transistor effect factors, with the kink current expressed as a function of channel length, carrier diffusion length, and drain saturation current, using hyperbolic secant and exponential relationships, eliminating empirical parameters and improving fitting accuracy across different gate voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the kink current calculation method based on floating body effect is used, then all possible current components through the back channel are considered, but the model involves many parameters and the current form is too complicated to be suitable for circuit simulation
Solution Approach 1:
The patent extracts and separates the dominant current components (impact ionization and parasitic bipolar transistor effects) from the complete floating body effect model. By taking out only the most significant contributions to kink current, the model achieves adequate accuracy while dramatically reducing the number of parameters and mathematical complexity, making it suitable for circuit simulation.
Solution Approach 2:
The patent employs a simplified model that sacrifices complete physical comprehensiveness for computational efficiency. By using an approximate model that captures the essential physics with fewer parameters, the calculation becomes computationally inexpensive and suitable for iterative circuit simulation processes.
2Device complexity
If empirical formulas with multiplication factor M are used, then the kink current can be calculated with fewer parameters, but the model cannot be well applied to the output characteristic curves at multiple gate voltages
Solution Approach 1:
The patent changes the functional form of the kink current model from an empirical multiplication factor approach to a physics-based formulation using hyperbolic secant functions. This parameter transformation allows the model to naturally adapt to different gate voltages by incorporating the parasitic bipolar transistor effect factor, which inherently accounts for voltage-dependent behavior without requiring separate fitting parameters for each condition.
Solution Approach 2:
The patent creates a universal model formulation that can handle multiple gate voltages and device conditions with a single set of physical parameters. The hyperbolic secant-based model structure provides multi-functionality by accurately describing kink current across different operating points without requiring recalibration, making it universally applicable to various SOI device configurations.
3Ease of operation
If a simplified kink current model is used, then the calculation is easier and suitable for circuit simulation, but the quantitative description accuracy is reduced
Solution Approach 1:
The patent transforms the mathematical parameters of the kink current model by introducing hyperbolic secant functions that naturally capture the physical behavior. This parameter transformation maintains calculation simplicity and simulation suitability while significantly improving quantitative accuracy, as the new parameters directly relate to physical device characteristics rather than empirical fitting constants.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method provides a more accurate and reliable calculation of kink current for SOI devices, suitable for circuit simulation, with parameters easily extracted and applicable to various channel lengths and gate voltages, enhancing the accuracy and applicability of kink current modeling.
Implementation Method 1
obtaining the impact ionization factor, the parasitic bipolar junction transistor effect factor, and the drain saturation current of the SOI device respectively
Implementation Method 2
Obtaining the channel length and the carrier diffusion length in the body region of the SOI device, and calculating the parasitic transistor effect factor of the SOI device according to the channel length and the carrier diffusion length in the body region
Data Source
AI summary
The present application discloses a method and apparatus for calculating the kink current of SOI device, which is used to solve the problem that the kink current calculation in the prior art is not accurate and is not suitable for circuit simulation. The method includes: obtaining the impact ionization factor, the parasitic transistor effect factor, and the drain saturation current of the SOI device respectively; and calculating the kink current of the SOI device according to the impact ionization factor, the parasitic transistor effect factor, and the drain saturation current.