Stress-Controlled Gate Electrodes for Semiconductor Transistors
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Solution Overview
Problem
Conventional semiconductor devices employing fully silicided polysilicon gate electrodes and stress control methods using liner nitride films face challenges such as tensile stress imbalance between Nch and Pch transistors, difficulty in securing contact regions as integration scale increases, and crystal defects due to liner nitride film cracks.
Innovation Solution
The use of gate electrodes made from materials causing different magnitudes of stress for Nch and Pch transistors, eliminating the need for a liner nitride film by selecting materials with varying tensile stress or density, and incorporating insulating sidewall spacers and trench-shaped isolation regions to optimize stress control and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liner nitride film is used for stress control, then transistor performance can be improved, but the film thickness must be increased significantly which makes it difficult to secure contact formation regions and causes crystal defects
Solution Approach 1:
The invention changes the material parameter of the gate electrode from conventional polysilicon to a stress control material with specific stress characteristics. This material parameter change enables stress control functionality without requiring the additional liner nitride film layer, thus avoiding the thickness and defect problems while maintaining transistor performance improvement.
Solution Approach 2:
The gate electrode is given multiple functions: it serves as both the electrical control element and the stress control element. By incorporating stress control capability directly into the gate electrode material, the separate liner nitride film for stress control becomes unnecessary, simplifying the overall device 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 enables effective stress control for both Nch and Pch transistors without liner nitride film defects, improving transistor performance and manufacturing feasibility even at increased integration scales.
Implementation Method 1
The first gate electrode and the second gate electrode are made of materials causing stresses of different magnitudes
Data Source
AI summary
A semiconductor device includes an Nch transistor having a first gate electrode and a Pch transistor having a second gate electrode. The first gate electrode and the second gate electrode are made of materials causing stresses of different magnitudes.