Nitride Layer Stress Engineering for Semiconductor Integration Density
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Solution Overview
Problem
As semiconductor devices become more highly integrated, the reduction in gate length and distance between adjacent gates poses challenges in maintaining performance and reliability, particularly in achieving high integration density and efficient transistor operation.
Innovation Solution
The use of a semiconductor device structure that includes a substrate with a gate structure, a first nitride layer rich in silicon, and a second nitride layer with a lower atomic percentage of silicon, which applies stress to the channel region to enhance charge mobility and reduce the narrow width effect, along with contact plugs that extend through these nitride layers to improve electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gate length and distance between adjacent gates are reduced to increase integration density, then integration density is improved, but charge mobility deteriorates and narrow width effect increases
Solution Approach 1:
The patent applies different stress conditions to different regions of the semiconductor device. Specifically, opposite stress directions are applied to adjacent transistor channels through strategically positioned nitride layers, creating localized stress fields that enhance charge mobility in each region without affecting the overall miniaturization and high integration density of the device
Solution Approach 2:
The patent changes the physical and chemical parameters of the nitride layers, including silicon content variation (first nitride layer has higher silicon content than second nitride layer), stress direction, and layer thickness. These parameter changes enable precise control over stress application to enhance charge mobility while maintaining compatibility with reduced gate dimensions
2Productivity
If gate length is reduced to increase integration density, then integration density is improved, but narrow width effect worsens
Solution Approach 1:
The patent implements localized stress application through nitride layers positioned adjacent to narrow gate structures. By creating non-uniform stress distribution concentrated at critical regions, the narrow width effect is mitigated locally without requiring increase in gate dimensions, thus preserving high integration density
3Productivity
If distance between adjacent gates is reduced to increase integration density, then integration density is improved, but impurity diffusion increases
Solution Approach 1:
The patent introduces nitride layers as intermediary structures between adjacent gates and active regions. These layers act as diffusion barriers that prevent impurity migration between closely spaced gates, enabling reduced gate spacing and higher integration density while maintaining device performance and reliability
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 configuration enhances charge mobility, reduces the narrow width effect, and improves the reliability of semiconductor devices by modifying the energy band structure and preventing impurity diffusion, thereby maintaining performance and integration density.
Implementation Method 1
a first nitride layer that includes silicon and covers opposing sidewall surfaces of each pair of the gates adjacent one another in the first direction, a second nitride layer that includes silicon, covers the first nitride layer on the opposing sidewall surfaces of the gates
Data Source
AI summary
A semiconductor device includes a substrate, a gate structure disposed on the substrate and which includes a gate insulating layer and a gate electrode layer, a first nitride layer disposed on the substrate and the gate structure and which includes silicon, and a second nitride layer that is disposed on the first nitride layer and has an atomic percentage of silicon less than that of the first nitride layer.