MISFET Stress Uniformity via Segmented Contact Layers
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Solution Overview
Problem
Semiconductor devices with MISFETs face variability in carrier mobility and current driving capacity due to differing stress levels in channel regions, influenced by the layout of gate electrodes and stress films, leading to inconsistent performance and power consumption.
Innovation Solution
The use of stress films, such as SiN, to induce tensile stress in n-type MISFETs and compressive stress in p-type MISFETs, combined with strategically placed contact layers to partition and manage stress films, ensuring consistent stress levels across channel regions, thereby enhancing carrier mobility and current driving capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If stress films are provided on MISFETs to enhance carrier mobility, then current driving capacity is improved, but stress levels vary significantly between different channel regions due to layout differences
Solution Approach 1:
The patent segments the stress film into multiple independent portions, each associated with specific gate electrodes. By providing contact holes that penetrate through specific stress film portions, the patent creates independently controllable stress regions, allowing uniform stress management across different channel regions despite layout variations.
Solution Approach 2:
The patent applies different stress film configurations to different local regions based on their specific layout characteristics. By selectively removing or penetrating stress films in certain areas while maintaining them in others, the patent achieves locally optimized stress conditions that result in overall uniformity across the device.
2Productivity
If multiple stress films are used to enhance carrier mobility in different regions, then overall device performance improves, but the complexity of stress management increases
Solution Approach 1:
The stress film is divided into multiple segments corresponding to different gate electrode regions. Each segment can be independently processed through selective contact hole formation, allowing simplified manufacturing steps rather than requiring complex simultaneous management of a unified stress film structure.
Solution Approach 2:
The stress film is formed preliminarily across the entire region before subsequent selective removal or penetration. This preliminary formation simplifies the overall process by establishing a uniform baseline structure that can then be selectively modified, rather than requiring complex simultaneous deposition patterns.
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 ensures that all MISFETs produce substantially equal stress, reducing dependence on gate electrode layout and improving the uniformity of semiconductor device performance and power efficiency.
Implementation Method 1
an insulation film for causing the channel region of a MIS transistor to produce stress is provided on the channel region
Data Source
AI summary
A semiconductor device includes a substrate, a semiconductor region provided in the substrate, a group of transistors including a plurality of MIS transistors and provided in the semiconductor region, the MIS transistors including a plurality of gate electrodes which extend in a first direction and are provided on the semiconductor region via gate insulation films, an insulation film provided on the group of transistors, and a first contact layer and a second contact layer extending in the first direction and provided on the semiconductor region at opposite sides of the group of transistors.