Flicker Noise Modeling for Small Semiconductor Devices
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Solution Overview
Problem
Traditional models fail to accurately describe the flicker noise phenomenon in advanced process transistors, particularly in terms of frequency and voltage dependence, as the number of effective defects decreases with device size, leading to inconsistent test results and an inability to correctly evaluate noise impact on circuit performance.
Innovation Solution
A physics-based modeling method for flicker noise in small-sized semiconductor devices, involving measurement, separation, and processing of noise spectrums to distinguish between Random Telegraph Noise defects and mobility fluctuation noise, using semiconductor parameter analyzers and low-frequency noise testers, and deriving a total current noise intensity model that accounts for dielectric and channel region contributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional carrier number fluctuation model is used to describe flicker noise, then the model can explain noise based on defect superposition, but it cannot accurately describe flicker noise in small-sized devices where the number of effective defects decreases
Solution Approach 1:
The patent segments the flicker noise into two distinct components: Random Telegraph Noise (RTN) from discrete defects and mobility fluctuation noise. By separating these noise sources and modeling them independently, the model can accurately describe both defect-dominated noise in larger devices and mobility-dominated noise in smaller devices, resolving the contradiction between traditional defect-based modeling and small-device behavior.
Solution Approach 2:
The patent introduces new parameters (Hooge coefficient αH, mobility fluctuation parameters) to complement or replace defect-based parameters depending on device size. This parameter transformation allows the model to adapt from defect-centric descriptions in larger devices to mobility-centric descriptions in smaller devices, maintaining accuracy across different device dimensions.
2Device complexity
If traditional models are used for advanced process devices, then the modeling approach remains simple, but the voltage dependence of noise test results shows great fluctuation and inconsistency
Solution Approach 1:
The patent makes the noise model dynamic by allowing the dominant noise mechanism to shift based on device operating conditions and dimensions. The model dynamically transitions between RTN-dominated behavior and mobility fluctuation-dominated behavior, enabling consistent prediction of noise across different voltage conditions and device sizes without requiring complex separate models for each regime.
Solution Approach 2:
The patent introduces mobility fluctuation as an intermediary mechanism that bridges the gap between defect-based noise and observed noise behavior in small devices. This intermediary model component provides a consistent physical basis for explaining voltage dependence across all device sizes, resolving the inconsistency in traditional defect-only models.
3Productivity
If device size is reduced to advance process nodes, then integration density increases, but the number of effective defects decreases making 1/f noise form unexplainable by defect superposition
Solution Approach 1:
The patent substitutes the mechanical defect-superposition mechanism with a mobility fluctuation mechanism for small devices. Instead of relying on the superposition of discrete defect effects (which requires many defects), the model uses mobility fluctuation theory that remains valid even when defect numbers are small, preserving the ability to explain 1/f noise form across all device sizes.
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 accurately describes the frequency and voltage dependence of flicker noise, providing a universal model applicable to different processes and circuit simulators, enhancing the accuracy of noise evaluation in circuit design and guiding the development of testing programs.
Implementation Method 1
The defects capture and emit carriers randomly, leading to the fluctuation of device threshold voltage and drain-source current
Implementation Method 2
The change of the defect state is described by elastic tunneling
Implementation Method 3
The source of flicker noise is the scattering (lattice scattering, surface roughness scattering, impurity scattering, etc.) of carriers in the channel region
Implementation Method 4
The source of flicker noise is the scattering (lattice scattering, surface roughness scattering, impurity scattering, etc.) of carriers in the channel region
Implementation Method 5
The source of flicker noise is the scattering (lattice scattering, surface roughness scattering, impurity scattering, etc.) of carriers in the channel region
Implementation Method 6
affect the mobility through mechanisms, such as Coulomb scattering
Data Source
AI summary
A modeling method of flicker noise of small-sized semiconductor device is provided, which includes steps of measuring flicker noise of the small-sized semiconductor device under different gate voltages to obtain device noise data; separating noise obtained by testing under the different gate voltages in frequency domain, to obtain noise spectrums resulted from Random Telegraph Noise (RTN) defects and a noise spectrum resulted from mobility fluctuation; processing the noise spectrums resulted from the changes of the charged states of the RTN defects to obtain Svg,I; processing the noise spectrum resulted from the mobility fluctuation to obtain Sid,II/III; and obtaining a total current noise intensity model, which is expressed as: Sid=Sid,I+Sid,II/III.