Semiconductor Isolation Trench Structure for Guard Ring Dislocation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor storage devices, crystal defects generated from the guard ring can extend to the element forming region, leading to potential device failure due to dislocation and electrical interference, which existing methods struggle to prevent effectively.
Innovation Solution
The semiconductor storage device incorporates an element isolation region with a trench shape and sub-trenches at the bottom corner, featuring a two-layer structure of thermal oxide and silicon oxide films, where the thermal oxide film is formed on the inner wall, creating a stress concentration point to generate crystal defects locally and reduce distortion, thereby preventing dislocation extension to the surface layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a guard ring surrounds the periphery of an element forming region, then electrical interference is reduced, but crystal defects and dislocations can extend to the element forming region causing device failure
Solution Approach 1:
The element isolation region is divided into a first element isolation region and a second element isolation region. The first element isolation region is formed in a guard ring region, while the second element isolation region is formed in a circuit isolation region. This segmentation isolates crystal defects generated in the guard ring from extending to the element forming region, while maintaining the electrical interference reduction function.
Solution Approach 2:
The first element isolation region acts as an intermediary barrier between the guard ring and the element forming region. It absorbs and isolates crystal defects and dislocations generated in the guard ring, preventing them from reaching the element forming region, while the guard ring continues to provide electrical interference reduction.
2Reliability
If element isolation regions are formed to prevent dislocation extension, then device reliability is improved, but the structure becomes more complex
Solution Approach 1:
The first element isolation region is formed to perform multiple functions: it isolates crystal defects from the element forming region, reduces distortion in the guard ring line, and prevents dislocation extension. By combining multiple protective functions into a single structural feature, the overall device complexity is minimized while achieving comprehensive reliability improvement.
Solution Approach 2:
The element isolation regions are strategically positioned in specific locations: the first element isolation region in the guard ring region where crystal defects are generated, and the second element isolation region in the circuit isolation region. This localized placement provides targeted protection where it is most needed, avoiding unnecessary structural complexity in other areas.
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 effectively reduces distortion in the guard ring line and prevents dislocations from extending to the surface layer of the circuit region, enhancing the reliability of the semiconductor storage device by selectively generating crystal defects at a stress concentration point, thus minimizing device failure.
Implementation Method 1
the thermal oxide film is formed on the inner wall, creating a stress concentration point to generate crystal defects locally and reduce distortion
Data Source
AI summary
A semiconductor storage device includes: a semiconductor substrate; a plurality of circuit regions; and an element isolation region having a trench shape formed between the circuit regions. In the element isolation region including a thermal oxide film and a silicon oxide film, a sub-trench is formed in a bottom corner portion, and the thermal oxide film covers at least an inner wall of the sub-trench.