Stacked Semiconductor Liners for Narrow Active Region Isolation
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Solution Overview
Problem
As the integration degree of semiconductor devices increases, the area occupied by the active region of a transistor decreases, making it difficult to form and maintain the active region, which deteriorates the characteristics of the semiconductor device.
Innovation Solution
A semiconductor device is fabricated using a method that involves forming a trench in a substrate, pretreating and post-treating semiconductor liners to remove contaminants, and stacking polysilicon liners to improve the active region's quality and reduce etching difficulties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the integration degree of semiconductor devices is increased, then the device density is improved, but the area of the active region decreases making it difficult to form and maintain
Solution Approach 1:
The patent divides the active region formation into multiple segments by forming a first semiconductor liner, then a second semiconductor liner, and finally a third semiconductor liner in sequence. This segmented approach allows each liner to contribute to the overall active region structure, enabling the formation of a sufficient active region area even as integration density increases.
Solution Approach 2:
The patent transitions from a single-layer liner approach to a multi-layer stacked structure, adding the vertical dimension of layering to solve the horizontal area constraint. By stacking multiple semiconductor liners (first, second, and third liners) vertically, the effective active region volume is increased without requiring additional lateral space.
2Device complexity
If a single semiconductor liner is formed, then the process is simple, but the active region characteristics deteriorate
Solution Approach 1:
The single semiconductor liner is segmented into multiple distinct liners (first, second, and third semiconductor liners), each potentially serving specific functions. This segmentation allows optimization of each layer's properties to collectively improve active region characteristics while maintaining manageable process complexity through systematic formation steps.
Solution Approach 2:
The patent employs a composite structure of multiple semiconductor liners stacked together, where each liner may have different material compositions or properties. This composite approach enables the combination of beneficial properties from different materials to achieve superior active region characteristics that cannot be obtained with a single material system.
3Reliability
If multiple semiconductor liners are stacked, then the active region quality is improved, but the process complexity increases
Solution Approach 1:
The patent applies preliminary actions by performing pretreatment before forming each semiconductor liner and post-treatment after forming each liner. These preliminary and post treatment steps prepare the surfaces and structures in advance, ensuring optimal conditions for subsequent liner formation and reducing potential defects, thereby improving active region quality while managing process complexity through systematic preparation.
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
The method enhances the semiconductor device's characteristics by increasing the active region's width and depth, reducing defects, and improving the quality of the device isolation layer, thus addressing the challenges of high integration density.
Implementation Method 1
sublimating the solid salt to expose a surface of the trench
Implementation Method 2
performing pretreatment before forming each of the semiconductor liners; performing post-treatment after forming each of the semiconductor liners
Data Source
AI summary
A semiconductor device including: a trench defining an active region in a substrate; a first semiconductor liner formed over the trench; a second semiconductor liner formed over the first semiconductor liner; and a device isolation layer formed over the second semiconductor liner and filling the trench. Disclosed is also a method for fabricating a semiconductor device, the method including: forming a trench defining an active region in a substrate; forming a plurality of semiconductor liners over the trench; performing pretreatment before forming each of the semiconductor liners; and performing post-treatment after forming each of the semiconductor liners.