Shallow Trench Isolation Edge Profile Modification via Gas Diffusion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices scale down, the inverse narrow width effect (INWE) leads to degraded performance due to reduced threshold voltage and current leakage issues in shallow trench isolation (STI) designs, particularly with sharp angled edges causing electrical isolation failures.
Innovation Solution
A method involving a patterned hard mask and oxygen-containing gas treatment to alter the edge profile of the substrate, transforming sharp angled edges into curved profiles within the shallow trench isolation (STI) regions, enhancing edge insulation and reducing current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shallow trench isolation (STI) is formed with sharp angled edges to provide electrical isolation, then the isolation effect is improved, but current leakage occurs and the inverse narrow width effect degrades device performance
Solution Approach 1:
The patent applies curvature by transforming the sharp angled edges of the STI into rounded edges through a chemical treatment process. The rounded edges eliminate the sharp corners that cause current leakage and inverse narrow width effect, while maintaining the electrical isolation function. This is achieved by exposing the STI to a vapor phase chemical that selectively modifies the edge geometry.
2Area of moving object
If the channel width of the transistor is reduced to scale down device size, then the integration density is improved, but the threshold voltage reduces and performance degrades due to inverse narrow width effect
Solution Approach 1:
By rounding the STI edges, the patent eliminates the sharp corners that create electric field concentration and cause inverse narrow width effect. This curvature modification allows transistors to maintain proper threshold voltage even at reduced channel widths, enabling continued device scaling without performance degradation.
3Reliability
If an oxide layer is formed on the side of the trench to further insulate the isolating material, then the electrical isolation is improved, but the sharp angled edges still cause current leakage through the oxide layer
Solution Approach 1:
The patent rounds the edges of the STI structure, which eliminates the sharp corners where current leakage occurs even through the oxide insulating layer. The curved edges distribute the electric field more evenly, preventing breakdown and leakage through the oxide layer while maintaining the insulating function.
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 curved edge profiles improve electrical isolation and reduce current leakage, thereby enhancing the performance and reliability of semiconductor devices by addressing the inverse narrow width effect and sharp edge-related issues in STI designs.
Implementation Method 1
a gas is driven-in through the exposed STI to alter an edge of the substrate on the first region
Data Source
AI summary
A method for fabricating semiconductor device is disclosed. First, a substrate having a first region and a second region is provided, a shallow trench isolation (STI) is formed in the substrate to separate the first region and the second region, and a patterned hard mask is formed on the first region and part of the STI, in which the patterned hard mask exposes includes an opening to expose part of the STI. Next, a gas is driven-in through the exposed STI to alter an edge of the substrate on the first region.