Deep Trench Isolation With Graded Dopant Regions
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Solution Overview
Problem
As the density of semiconductor devices on a substrate increases, maintaining effective electrical isolation between them becomes challenging, leading to variations in isolation levels across the substrate and difficulties in regulating parasitic field effect transistor currents and punch-through currents.
Innovation Solution
A deep trench isolation structure is implemented, featuring a dielectric-lined isolation trench with semiconducting regions of varying dopant concentrations to enhance electrical isolation, including a first semiconducting region with a higher dopant concentration to suppress parasitic FET currents and a second region to increase turn-on voltage, thereby improving isolation between adjacent devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If device density is increased, then productivity is improved, but electrical isolation between devices deteriorates
Solution Approach 1:
The patent applies local quality by creating distinct dopant concentration zones within the isolation structure. The first semiconducting region has a higher dopant concentration than the second semiconducting region, which in turn has a higher concentration than the bulk semiconductor body. This gradient structure provides enhanced electrical isolation locally at the isolation trench interface while allowing high device density elsewhere on the substrate.
Solution Approach 2:
The patent changes the dopant concentration parameter across different regions of the isolation structure. By increasing dopant concentration in the first semiconducting region relative to the bulk material, and creating a gradient through the second region, the patent modifies the electrical properties to suppress parasitic currents and improve isolation effectiveness, enabling higher device density without compromising isolation.
2Productivity
If device density is increased, then productivity is improved, but parasitic FET currents become harder to regulate
Solution Approach 1:
The patent addresses parasitic FET currents by creating a localized high-dopant concentration region (first semiconducting region) at the isolation trench interface. This local modification raises the turn-on voltage of parasitic FETs formed at the trench edges, effectively suppressing these harmful currents without requiring changes to the overall device layout or density.
Solution Approach 2:
The patent changes the dopant concentration parameter in the first semiconducting region to a level higher than both the bulk material and the second semiconducting region. This parameter change increases the voltage required to activate parasitic FET channels, thereby suppressing parasitic currents while allowing high device density to be maintained.
3Productivity
If device density is increased, then productivity is improved, but punch-through currents become harder to block
Solution Approach 1:
The patent suppresses punch-through currents by creating a localized high-dopant concentration region (first semiconducting region) at the isolation trench interface adjacent to the device region. This local quality enhancement creates a potential barrier that blocks punch-through currents between adjacent devices, enabling higher device density without compromising current blocking capability.
Solution Approach 2:
The patent modifies the dopant concentration parameter in the first semiconducting region to exceed that of the bulk material and second region. This parameter change creates a higher potential barrier that effectively blocks punch-through currents, allowing increased device density while maintaining effective current isolation between devices.
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 deep trench isolation structure effectively suppresses parasitic FET and punch-through currents at higher voltages, maintaining high electrical isolation and allowing for increased device density without electrical breakdown, thus enhancing the packing density of semiconductor devices.
Implementation Method 1
The first dopant concentration is greater than the body dopant concentration and also is greater than the second dopant concentration. The higher dopant concentration in the first semiconducting region increases a turn-on voltage of a parasitic field effect transistor (FET) that can be present within a semiconductor device
Implementation Method 2
A dielectric material extends within the isolation trench. The deep trench isolation structure effectively suppresses parasitic FET and punch-through currents at higher voltages, maintaining high electrical isolation
Data Source
AI summary
Deep trench isolation structures and systems and methods including the same are disclosed herein. The systems include a semiconductor device. The semiconductor device includes a semiconductor body, a device region, and the deep trench isolation structure. The deep trench isolation structure is configured to electrically isolate the device region from other device regions that extend within the semiconductor body. The deep trench isolation structure includes an isolation trench, a dielectric material that extends within the isolation trench, a first semiconducting region, and a second semiconducting region. The methods include methods of operating an integrated circuit device that includes a plurality of semiconductor devices that include the disclosed deep trench isolation structures.