High-k Dielectric Work-Function Adjustment for Threshold Voltage Control
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Solution Overview
Problem
The scaling-down of MOS transistors in semiconductor devices leads to degradation in operational characteristics, particularly in achieving improved electric characteristics and managing threshold voltages across transistors with different conductivity types.
Innovation Solution
A semiconductor device design incorporating high-k dielectric layers with work-function adjusting materials, where the first high-k dielectric layer includes a first work-function adjusting material and the second and third high-k dielectric layers include a second work-function adjusting material, allowing for the adjustment of effective work functions and threshold voltages of gate electrodes, thereby improving electric characteristics and enabling transistors with different threshold voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If MOS transistors are scaled down to increase integration density, then device size is reduced, but operational characteristics deteriorate
Solution Approach 1:
The patent applies local quality by using different work-function adjusting materials in different high-k dielectric layers to create spatially varying electrical properties. Specifically, a first work-function adjusting material is used in a first high-k dielectric layer for transistors requiring a first threshold voltage, while a second work-function adjusting material is used in a second high-k dielectric layer for transistors requiring a second threshold voltage. This allows different regions of the semiconductor device to have optimized electrical characteristics tailored to their specific functional requirements, thereby maintaining reliable operation despite overall device scaling.
2Adaptability or versatility
If transistors with different threshold voltages are integrated, then device functionality is improved, but manufacturing complexity increases
Solution Approach 1:
The patent implements segmentation by dividing the high-k dielectric structure into multiple distinct layers, each containing a different work-function adjusting material. The first high-k dielectric layer contains a first work-function adjusting material, while the second high-k dielectric layer contains a second work-function adjusting material. This segmentation allows independent optimization of threshold voltages for different transistor types (e.g., NFET and PFET) within the same semiconductor device, enabling enhanced functionality while maintaining a systematic manufacturing approach.
Solution Approach 2:
The patent employs composite materials by combining different work-function adjusting materials within the high-k dielectric structure. Rather than using a single uniform material throughout, the invention integrates multiple materials with different work-function properties into a unified device architecture. This composite approach enables precise control over threshold voltages for different transistor regions, achieving versatile device functionality while leveraging the complementary properties of different materials.
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 enhances the electric characteristics of semiconductor devices by effectively managing threshold voltages and preventing deterioration, allowing for transistors with varying threshold voltages to be integrated without compromising performance.
Implementation Method 1
The first high-k dielectric layer may include a first work-function adjusting material, and the second and third high-k dielectric layers may include a second work-function adjusting material
Implementation Method 2
The first high-k dielectric layer may include a first work-function adjusting material, and the second and third high-k dielectric layers may include a second work-function adjusting material
Implementation Method 3
a first high-k dielectric layer between the first gate electrode and the semiconductor substrate, a second high-k dielectric layer between the second gate electrode and the semiconductor substrate, and a third high-k dielectric layer between the second gate electrode and the second high-k dielectric layer
Data Source
AI summary
A semiconductor device includes a semiconductor substrate including multiple active regions having a common conductivity type and separate, respective gate electrodes on the separate active regions. Different high-k dielectric layers may be between the separate active regions and the respective gate electrodes on the active regions. Different quantities of high-k dielectric layers may be between the separate active regions and the respective gate electrodes on the active regions. The different high-k dielectric layers may include different work-function adjusting materials.