Gate Spacer Structure for Semiconductor Devices
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Solution Overview
Problem
In semiconductor manufacturing, the formation of source/drain layers during the SEG process can be defective due to outgassing of carbon from oxygen-containing silicon patterns, and existing gate spacer structures are prone to damage during wet etching processes.
Innovation Solution
A semiconductor device and manufacturing method that incorporate a gate spacer structure with a wet etch stop pattern, an oxygen-containing silicon pattern, and an outgassing reduction or prevention pattern, which prevents carbon outgassing and protects the spacer structure during wet etching by using materials like silicon nitride and silicon dioxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an oxygen-containing silicon pattern is used in the gate spacer structure, then the spacer structure provides proper material for etching processes, but carbon outgassing occurs during SEG process causing defects in source/drain layers
Solution Approach 1:
The gate spacer structure is divided into multiple functional layers: a lower portion containing the oxygen-containing silicon pattern for etching process compatibility, and an upper portion containing the outgassing prevention pattern to block carbon outgassing during SEG. This segmentation allows each layer to perform its specific function without interfering with the other, resolving the contradiction between etching compatibility and source/drain layer quality.
Solution Approach 2:
The outgassing prevention pattern acts as an intermediary layer between the oxygen-containing silicon pattern and the source/drain layer formation process. It mediates the conflict by allowing the lower portion to maintain etching compatibility while the upper portion prevents carbon outgassing from reaching the source/drain layer, thus protecting the layer quality.
2Device complexity
If a simple gate spacer structure is used, then the manufacturing process is simpler, but the spacer structure is prone to damage during wet etching processes
Solution Approach 1:
The gate spacer structure is segmented into multiple layers with distinct functions: the lower portion provides structural support and etching resistance, while the upper portion provides outgassing prevention. This segmentation enhances the overall reliability of the structure during manufacturing processes without significantly complicating the fabrication流程.
Solution Approach 2:
The gate spacer structure uses a composite design combining different material properties in vertical layers. The lower portion uses oxygen-containing silicon for etching process compatibility, while the upper portion uses outgassing prevention material for protecting against carbon outgassing. This composite structure provides both mechanical integrity and functional performance during manufacturing.
3Ease of manufacture
If the dummy gate structure is removed to form an opening, then the gate structure can be formed, but the spacer structure may be damaged during the removal process
Solution Approach 1:
The outgassing prevention pattern is formed in advance on the upper portion of the gate spacer structure before the dummy gate removal process. This preliminary action ensures that when wet etching is performed to remove the dummy gate, the spacer structure is already protected and less susceptible to damage, maintaining its integrity throughout the gate formation process.
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 solution effectively prevents defects in source/drain layers by reducing carbon outgassing and ensures the integrity of the gate spacer structure, maintaining its functionality and structure during the transition from dummy to gate structures.
Implementation Method 1
an outgassing reduction or prevention pattern, which reduces or prevents carbon outgassing during the SEG process
Implementation Method 2
a wet etch stop pattern, which stops wet etching to prevent damage to the gate spacer structure
Implementation Method 3
a selective epitaxial growth (SEG) process may be performed to form a source/drain layer in the recess
Data Source
AI summary
A semiconductor device includes an active fin on a substrate, a gate structure on the active fin, a gate spacer structure on a sidewall of the gate structure, and a source/drain layer on at least a portion of the active fin adjacent the gate spacer structure. The gate spacer structure includes a wet etch stop pattern, an oxygen-containing silicon pattern, and an outgas sing prevention pattern sequentially stacked.