Vertical FinFET Neutralized Regions for Edge-Uniform Conductor Routing
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Solution Overview
Problem
Existing vertical power transistors face challenges in achieving uniform device characteristics and minimizing electrical variations due to non-uniformity in lithography, etch, and regrowth processes, particularly at the edges of the array, leading to variations in fin width, height, and dopant incorporation, which affect leakage current and threshold voltage.
Innovation Solution
The introduction of inactive fins and neutralized regions with reduced electrical conductivity, achieved through ion implantation or hydrogen plasma treatment, allows for the deposition of electrical conductors without significant current flow to underlying layers, thereby reducing edge effects and enhancing uniformity in the FinFET array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If vertical FinFET arrays are fabricated with high density, then device area is reduced and integration is improved, but uniformity of lithography, etch, and regrowth processes deteriorates due to variations in pattern density
Solution Approach 1:
The patent introduces inactive fins at specific locations (edges and corners) of the FinFET array to create local variations in pattern density. These inactive fins are strategically placed to improve lithography, etch, and regrowth uniformity in edge regions without affecting the active device performance in the center of the array. This local modification resolves the contradiction by improving manufacturing precision in critical areas while maintaining high device area density.
Solution Approach 2:
The patent segments the FinFET array into active regions and inactive regions by introducing dummy fins at edges and corners. This segmentation allows different parts of the array to have different functions: the center region maintains high density for performance, while the edge regions include inactive fins to improve process uniformity. The segmentation enables simultaneous optimization of both device area utilization and manufacturing precision.
2Device complexity
If edge effects are present in FinFET arrays, then manufacturing complexity is reduced, but uniformity of electrical characteristics deteriorates
Solution Approach 1:
The patent applies local quality by introducing inactive fins specifically at edge and corner regions where edge effects occur, while leaving the active device regions unchanged. This localized approach improves electrical characteristic uniformity at edges without adding complexity to the overall device structure or affecting the performance of active fins in the array center.
Solution Approach 2:
The inactive fins act as intermediary elements that mediate between the active device regions and the edge regions. These dummy fins provide a transition zone that compensates for edge effects in lithography, etch, and regrowth processes, thereby improving electrical characteristic uniformity without requiring complex modifications to the active device structure.
3Manufacturing precision
If inactive fins are added to improve uniformity, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The patent implements local quality by placing inactive fins only where needed (at edges and corners) rather than throughout the entire array. This selective approach improves manufacturing precision in critical edge regions while minimizing the increase in overall device complexity. The inactive fins are confined to specific zones and do not interfere with active device operation.
Solution Approach 2:
The inactive fins can be considered as temporary or disposable structural elements that are introduced solely to improve process uniformity during manufacturing. They do not contribute to the final active device function and can be easily removed or left as non-interfering structures. This principle allows the patent to accept the added complexity of inactive fins as a necessary trade-off for achieving superior manufacturing precision.
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 improves the uniformity of device characteristics across the FinFET array, reduces junction leakage, and minimizes electrical variations, leading to more reliable and efficient high-voltage operation.
Implementation Method 1
The neutralized region can include implanted ions. The second electrical conductivity of the first fin tip and the second fin tip can be achieved using hydrogen plasma treatment.
Implementation Method 2
The second electrical conductivity of the first fin tip and the second fin tip can be achieved using hydrogen plasma treatment.
Data Source
AI summary
A vertical, FinFET device includes an array of FinFETs comprising a plurality of rows and columns of fins. Each of the fins has a fin length and a fin width, a first fin tip, a second fin tip, and a central region disposed between the first fin tip of a first row of the plurality of rows and the second fin tip of a second row of the plurality of rows. The central region is characterized by an electrical conductivity. The FinFET device also includes a neutralized region including the first fin tip, a region between the first row of the plurality of rows and the second row of the plurality of rows, and the second fin tip. The neutralized region is characterized by a second electrical conductivity less than the electrical conductivity of the central region. The FinFET device further includes an electrical conductor disposed over the neutralized region.