FinFET Channel Stress Tuning for Precise Current Control
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Solution Overview
Problem
Current integrated circuit devices face challenges in scaling and current control due to the short channel effect and difficulty in adjusting channel width, particularly in fin-shaped transistors, which affects the efficiency of carrier mobility and current amounts.
Innovation Solution
The integration of fin-shaped transistors with varying source/drain thicknesses and recess depths, along with different stress applications and impurity concentrations, allows for independent control of current amounts by adjusting the thickness and stress applied to the channels, enabling improved carrier mobility and current efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fin-shaped transistors are used for scaling, then device density increases, but current control capability deteriorates due to short channel effect
Solution Approach 1:
The patent applies different stress conditions to different regions of the channel by varying source/drain thicknesses. Specifically, PMOS transistors use thicker source/drains to apply compressive stress, while NMOS transistors use thinner source/drains to apply tensile stress. This local differentiation of stress conditions improves carrier mobility and current control in each transistor type without compromising the overall scaling benefits of the fin-shaped structure.
Solution Approach 2:
The patent changes physical parameters of the source/drain regions, specifically the thickness dimension, to control the stress applied to the channel. By adjusting the source/drain thickness parameter, the patent optimizes the stress magnitude and type (tensile or compressive) to enhance carrier mobility. This parameter adjustment allows independent optimization of current control for different transistor types within the same scaled device architecture.
2Ease of manufacture
If uniform source/drain thickness is used, then manufacturing simplicity is maintained, but current control precision deteriorates
Solution Approach 1:
The patent implements local quality differentiation by assigning different source/drain thicknesses to different transistor types (PMOS vs NMOS) within the same integrated circuit. This allows each transistor type to have optimized stress conditions tailored to its specific carrier mobility requirements, achieving precise current control without requiring complex individual customization of each transistor.
Solution Approach 2:
The patent utilizes parameter changes in the source/drain thickness dimension to control the stress state of the channel. By varying this geometric parameter, the patent achieves different stress magnitudes and types (tensile or compressive) that directly influence carrier mobility. This parameter-based control mechanism enables precise current adjustment while maintaining compatibility with standard semiconductor manufacturing processes.
3Productivity
If stress is applied to enhance carrier mobility, then current efficiency improves, but device complexity increases
Solution Approach 1:
The patent applies stress locally to the channel region through the source/drain structures, creating a stress field precisely where it is needed to enhance carrier mobility. This localized stress application avoids the need for complex external stress application mechanisms while achieving the desired effect in the critical current flow path.
Solution Approach 2:
The patent employs parameter changes in source/drain thickness to control the stress magnitude and type. By adjusting this geometric parameter during manufacturing, the patent optimizes carrier mobility without requiring additional complex stress application structures or mechanisms. The stress is inherently generated by the dimensional mismatch between source/drain and channel regions.
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
This approach effectively enhances carrier mobility and current efficiency by varying the thickness and stress applied to the channels, allowing for precise control of current amounts in integrated circuit devices, particularly in fin-shaped transistors.
Implementation Method 1
a first stress applied by the first source/drain to a first channel of the first fin-shaped transistor is different from a second stress applied by the second source/drain to a second channel of the second fin-shaped transistor
Data Source
AI summary
An integrated circuit device includes a first transistor having a first channel between a first source/drain, and a second transistor having a second channel between a second source/drain. The first transistor operates based on a first amount of current and the second transistor operates based on a second amount of current different from the first amount of current. The first and second channels have fixed channel widths. The fixed channel widths may be based on fins or nanowires included in the first and second transistors.