Boron Filled Trench Isolation Structures
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Solution Overview
Problem
Conventional trench isolation structures in semiconductor devices often form voids during the filling process, especially in high aspect ratio trenches, leading to improper filling and ineffective isolation due to the limitations of oxide filling materials.
Innovation Solution
Using boron as a trench filler material, deposited through an atomic layer deposition technique or chemical vapor deposition, which is more resistant and less prone to void formation, and forming a barrier or adhesion layer to prevent diffusion and enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If oxide filling is used in high aspect ratio trenches, then the filling process becomes difficult, but void formation increases and isolation effectiveness decreases
Solution Approach 1:
The patent changes the material parameter from oxide to boron, which has different physical and chemical properties including lower vapor pressure and better conformal deposition characteristics, enabling successful filling of high aspect ratio trenches without void formation
Solution Approach 2:
The patent replaces the chemical vapor deposition process with atomic layer deposition, which provides better control over the deposition process and enables complete filling of high aspect ratio trenches by depositing material in atomic layers
2Reliability
If trench aspect ratio increases, then isolation capability improves, but void formation during filling increases
Solution Approach 1:
The patent changes the filling material from oxide to boron, which can be deposited conformally in high aspect ratio trenches without forming voids, thus maintaining filling completeness while achieving the required isolation capability
Solution Approach 2:
The patent introduces a barrier layer as an intermediary between the trench wall and the boron filling material, which prevents boron diffusion into the substrate and enables complete filling of high aspect ratio trenches
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 boron-filled apertures provide effective electrical isolation with reduced leakage currents and voids, enabling reliable filling of high aspect ratio trenches and improving the integrity of semiconductor device isolation structures.
Implementation Method 1
deposited through an atomic layer deposition technique
Implementation Method 2
chemical vapor deposition
Implementation Method 3
forming a barrier or adhesion layer to prevent diffusion and enhance adhesion
Data Source
AI summary
An isolation structure, such as a trench isolation structure, may be formed by forming an aperture in a semiconductor substrate and then filling the aperture with boron. In some embodiments, the aperture filling may use atomic layer deposition. In some cases, the boron may be amorphous boron. The aperture may be a high aspect ratio aperture, such as a trench, in some embodiments.