Guard Ring Barrier Structure for Semiconductor Device Isolation
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Solution Overview
Problem
The increasing integration level in semiconductor devices leads to increased parasitic capacitance and reduced operating reliability due to closer distances between the gate and bit line, causing gate oxide integrity and unlimited sensing delay failures, which are exacerbated by the oxidation of barrier metal layers during the gate oxidation process, necessitating larger distances that increase die size and reduce cost efficiency.
Innovation Solution
A semiconductor device with a guard ring region acting as a barrier structure between the cell and peripheral regions, featuring a buried-type gate and bit line contact plug, using tungsten and titanium nitride films to prevent oxygen ion migration and maintain gate integrity, thereby ensuring the reliability of the semiconductor device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the integration level is increased to reduce die size, then the area and cost efficiency are improved, but parasitic capacitance increases and operating reliability deteriorates due to closer distances between gate and bit line
Solution Approach 1:
The device is divided into distinct cell region and peripheral region with a guard ring structure acting as a barrier between them. This segmentation prevents oxygen ion migration from the peripheral region to the cell region, maintaining gate oxide integrity while allowing high integration density in the cell region.
Solution Approach 2:
A guard ring structure comprising a barrier metal layer (titanium nitride) and conductive material (tungsten) is introduced as an intermediary between the cell region and peripheral region. This intermediate structure blocks oxygen ion migration paths while maintaining electrical functionality and allowing reduced die size.
2Reliability
If the distance between cell region and peripheral region is increased to prevent oxygen ion migration, then gate oxide integrity is maintained, but die size increases and cost efficiency decreases
Solution Approach 1:
The guard ring structure serves as an intermediary barrier that blocks oxygen ion migration without requiring increased spacing between regions. The barrier metal layer (titanium nitride) specifically targets and blocks oxygen ions, while the conductive material maintains electrical connectivity, thus preserving gate oxide integrity within compact dimensions.
Solution Approach 2:
The invention changes the protective parameter from physical distance to material composition. Instead of relying on large spacing, a thin film barrier structure with specific materials (titanium nitride and tungsten) is used to block oxygen ions, enabling compact design while maintaining gate oxide integrity.
3Ease of manufacture
If a conventional device isolation structure is used without a guard ring, then manufacturing is simpler, but oxygen ion migration occurs during gate oxidation causing gate oxide integrity and unlimited sensing delay failures
Solution Approach 1:
The barrier metal layer (titanium nitride) and conductive material are formed in the guard ring structure before the gate oxidation process. This preliminary action creates a protective barrier that prevents oxygen ions generated during subsequent oxidation steps from migrating to the cell region, thereby preventing GOI and USD failures.
Solution Approach 2:
The guard ring structure with barrier metal layer acts as an intermediary that blocks the harmful effect of oxygen ions during the gate oxidation process. This intermediate structure allows the oxidation process to proceed normally in the peripheral region while protecting the cell region from oxygen contamination.
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 guard ring structure effectively prevents oxygen ion migration, maintaining gate integrity and preventing gate oxide integrity and unlimited sensing delay failures, while allowing for a reduced distance between the cell and peripheral regions, thus improving yield and cost efficiency by allowing for a smaller die size.
Implementation Method 1
the TiN film which is a barrier metal layer (not shown) of the buried-type gate 25 is oxidized. The oxidation of the barrier metal layer causes a gate oxide integrity (GOI) fail
Implementation Method 2
electric separation between a bit line and a bit line contact plug formed on the semiconductor substrate is more clearly defined
Data Source
AI summary
A semiconductor device including a cell region and a peripheral region, the semiconductor device comprising: a guard ring region provided between the cell region and the peripheral region, the guard ring region having a barrier structure.