FinFET Spacer Stress Segmentation for Leakage Reduction
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Solution Overview
Problem
Current semiconductor devices face challenges in meeting critical dimension requirements and improving performance due to limitations in stress management for fin structures, particularly in fin field effect transistors (FinFETs), where stress effects are not adequately addressed to optimize carrier mobility and minimize leakage between source and drain.
Innovation Solution
The semiconductor device incorporates fin structures with spacers of different stress types (compressive and tensile) on a substrate, where the thickness of these spacers is less than the height of the fin, and an insulating layer is used to cover and overlap these spacers, enhancing stress management and carrier mobility. The manufacturing method involves depositing stress materials and using resist patterns to form these spacers, ensuring precise stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stress materials are added to fin structures to improve carrier mobility, then device performance is improved, but device complexity increases
Solution Approach 1:
The stress management system is segmented into multiple spacers positioned at different locations around the fin structure. Each spacer can be independently configured with specific stress types (tensile or compressive), allowing targeted stress application to different regions of the fin structure without requiring a complete redesign of the entire device architecture.
Solution Approach 2:
Spacers are introduced as intermediary elements between the gate electrode and the fin structure. These spacers serve as stress mediators that transmit mechanical stress to the fin structure to enhance carrier mobility, while also functioning as part of the gate stack structure. This intermediary approach allows stress management without fundamentally altering the core FinFET architecture.
2Reliability
If multiple spacers with different stress types are used to optimize carrier mobility, then device performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
Different spacers are assigned different stress types (tensile or compressive) and different thicknesses based on their specific locations and the local requirements of the fin structure. For example, spacers adjacent to the channel region may have different stress characteristics than those near the source or drain regions. This localized optimization allows carrier mobility enhancement without requiring uniform high-precision control across all spacers.
Solution Approach 2:
The invention utilizes parameter changes in spacer thickness and stress type to optimize device performance. By varying the thickness of spacers (with at least one spacer having thickness less than the fin height) and selecting different stress types for different spacers, the system achieves enhanced carrier mobility while managing manufacturing complexity through parameter optimization rather than structural complexity.
3Object-generated harmful factors
If spacer thickness is reduced to less than fin height to minimize leakage, then leakage between source and drain is reduced, but stress management capability is limited
Solution Approach 1:
The stress management function is segmented across multiple spacers of varying thicknesses. At least one spacer has a thickness less than the fin height to minimize leakage, while other spacers can have greater thickness to provide enhanced stress management. This segmentation allows the system to achieve both low leakage and effective stress optimization by distributing different functional requirements across multiple components.
Solution Approach 2:
The gate structure is formed as a composite structure incorporating multiple spacers with different stress types and thicknesses. This composite approach allows the system to simultaneously achieve leakage reduction (through thin spacers) and stress optimization (through thicker spacers with appropriate stress types), combining the benefits of different spacer configurations within a single integrated structure.
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 minimizes carrier mobility in desired regions, reduces leakage between the source and drain, and optimizes device performance by effectively utilizing stress effects in FinFETs.
Implementation Method 1
stress effects are not adequately addressed to optimize carrier mobility and minimize leakage between source and drain
Data Source
AI summary
A semiconductor device includes a substrate that has a surface. The semiconductor further includes a fin disposed on the surface and including a semiconductor member. The semiconductor further includes a spacer disposed on the surface, having a type of stress, and overlapping the semiconductor member in a direction parallel to the surface. A thickness of the spacer in a direction perpendicular to the surface is less than a height of the semiconductor member in the direction perpendicular to the surface.