Semiconductor Capacitor Isolation Trench for Leakage Reduction
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Solution Overview
Problem
Conventional semiconductor structures, such as DRAM, are prone to electric leakage between the capacitor and the substrate, which degrades their electrical performance.
Innovation Solution
A semiconductor structure and formation method that involves forming a substrate with a semiconductor layer having first trenches, an isolation trench, and a first spacer to electrically isolate the capacitor from the substrate, reducing leakage by using a dielectric material to create a spacer that communicates with the trenches and supports the capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor structure is used, then the fabrication process is simple, but electric leakage between the capacitor and substrate occurs
Solution Approach 1:
The patent introduces an isolation trench filled with insulating material as an intermediary structure between the capacitor and substrate. This isolation trench acts as a mediator that electrically separates the capacitor from the substrate, preventing direct leakage paths while maintaining the overall capacitor structure. The intermediary isolation layer blocks charge leakage without requiring fundamental changes to the capacitor electrodes or dielectric layers.
Solution Approach 2:
The patent segments the semiconductor structure by dividing it into distinct functional regions separated by isolation trenches. The capacitor structure is segmented from the substrate through intermediate isolation layers, creating separate electrical domains. This segmentation allows independent optimization of the capacitor region while providing electrical isolation from the substrate, reducing leakage without affecting capacitor performance.
2Reliability
If isolation structures are added to reduce leakage, then electrical performance improves, but fabrication complexity increases
Solution Approach 1:
The patent merges the isolation structure formation with the existing capacitor fabrication process. The isolation trenches are formed and filled with insulating material during the same fabrication sequence as the capacitor electrodes and dielectric layers. By combining the isolation structure creation with the capacitor fabrication steps, the patent achieves electrical isolation without requiring separate, additional manufacturing processes, thus maintaining ease of manufacture while improving electrical performance.
3Reliability
If the capacitor is directly formed on the substrate, then the structure is compact, but leakage paths exist between capacitor and substrate
Solution Approach 1:
The patent addresses the leakage problem by transitioning from a two-dimensional planar layout to a three-dimensional vertical structure. Isolation trenches are formed extending vertically through the substrate, and insulating material is deposited to fill these trenches, creating vertical isolation barriers. This dimensional change allows electrical isolation without increasing the planar footprint of the capacitor, maintaining structural compactness while eliminating leakage paths through the third dimension.
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 electric leakage between the capacitor and the substrate, enhancing the electrical performance of the semiconductor structure while simplifying the fabrication process and reducing costs.
Implementation Method 1
forming, in the semiconductor layer, an isolation trench positioned below the first trenches, where the isolation trench extends along the first direction and continuously communicates with the plurality of first trenches; forming a first spacer at least positioned in the isolation trench
Data Source
AI summary
Embodiments relate to a semiconductor structure and a formation method thereof. The method for forming a semiconductor structure includes: forming a substrate and a semiconductor layer positioned above the substrate, where the semiconductor layer includes first trenches spaced along a first direction, the first direction being a direction parallel to a top surface of the substrate; forming, in the semiconductor layer, an isolation trench positioned below the first trenches, where the isolation trench extends along the first direction and continuously communicates with the first trenches; forming a first spacer at least positioned in the isolation trench; and forming a capacitor above the first spacer. The semiconductor structure and the formation method thereof reduce electric leakage between the substrate and the capacitor, thereby improving electrical performance of the semiconductor structure.