Adjusted Deep N-Well Structure for Noise and Punch-Through Isolation
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Solution Overview
Problem
The decreasing size of transistors in semiconductor devices leads to increased noise levels and unintended current flows due to closer component distances, which can result in noise and punch-through failures, particularly in high-voltage Field Effect Transistor (FET) applications.
Innovation Solution
The implementation of a triple-well structure with adjusted deep N-wells, where the wells are formed by implanting doping material through patterned masks, creating unique physical characteristics such as depth transitions and adjusted separation distances, which reduce noise levels and enhance connection strength while minimizing the risk of punch-through failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transistor size is decreased to increase component density, then device integration density is improved, but noise levels and unintended current flows increase
Solution Approach 1:
The invention divides the semiconductor structure into multiple isolated wells (first well, second well, third well) with different doping types and depths. This segmentation creates electrical isolation between adjacent transistors, preventing noise coupling and unintended current flows while maintaining high component density on the substrate.
Solution Approach 2:
The invention implements localized doping variations within the substrate, creating regions with different doping types (n-type and p-type) and depths. The third well extends deeper than the first and second wells in specific regions, providing localized electrical isolation where needed while maintaining standard well structures in other areas, thus addressing noise issues without compromising overall device performance.
2Productivity
If distance between transistors is decreased to increase density, then integration density is improved, but punch-through failures increase
Solution Approach 1:
The invention extends the isolation structure into the vertical dimension by creating a third well that extends deeper into the substrate than the first and second wells. This depth transition provides an additional spatial dimension for electrical isolation, preventing punch-through failures between adjacent transistors even when their horizontal spacing is minimized for high density integration.
Solution Approach 2:
The invention nests multiple wells within each other, with the third well (deeper, different doping type) nested within the region defined by the first and second wells. This nested structure creates layered electrical isolation, where the deeper third well provides an additional barrier against punch-through while the shallower first and second wells provide isolation at upper levels.
3Ease of manufacture
If conventional well structures are used in high-voltage FET applications, then manufacturing simplicity is maintained, but noise and punch-through issues occur
Solution Approach 1:
The invention modifies the conventional well structure by changing key parameters: adding a third well with different doping type, increasing the depth of the third well relative to the first and second wells, and positioning the third well to extend between regions underlying adjacent gate structures. These parameter changes enhance noise immunity and prevent punch-through while maintaining compatibility with standard semiconductor manufacturing processes.
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 reduces noise levels, improves state transitions, and enhances connection strength between wells, effectively addressing punch-through issues without adding complexity or cost to the manufacturing process, thereby improving the reliability and performance of semiconductor devices.
Implementation Method 1
The adjusted wells can be formed by implanting the doping material through patterned masks (e.g., oxide nitride masks) instead of implanting before the masking step
Data Source
AI summary
Semiconductor devices including an adjusted bottom/deep well embedded in a semiconductor substrate. The adjusted bottom/deep well having one or more characteristics resulting from being formed using or through a temporary masked layer.