FinFET Diode Active Area Optimization via Segmented Fins
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Solution Overview
Problem
FinFET diodes exhibit reduced efficiency due to the presence of plural fin structures, which decreases the active area for producing injection current compared to traditional planar diodes.
Innovation Solution
A method for fabricating a FinFET diode with enhanced efficiency involves forming elongated semiconductor fin structures, dielectric strips for insulation, and doped regions, where the fin structures are divided into separate p-type and n-type regions, and the gate structures are inactive, allowing for improved current production by optimizing the number of fin structures and dielectric isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If FinFET structure is used to build diodes, then device density and fabrication compatibility are improved, but diode efficiency decreases due to reduced active area
Solution Approach 1:
The semiconductor substrate is divided into multiple discrete fin structures that are spatially separated by dielectric material. This segmentation allows each fin to function as an independent current path while collectively providing sufficient active area, resolving the contradiction between maintaining FinFET density advantages and achieving adequate diode efficiency through increased total active area across multiple separated fins
Solution Approach 2:
The patent transitions from planar diode architecture to three-dimensional FinFET architecture, utilizing vertical fin structures extending from the substrate surface. This dimensional change enables better chip area efficiency and maintains fabrication compatibility while the multiple fins collectively provide sufficient active area to overcome the efficiency reduction from individual fin geometry
2Productivity
If multiple fin structures are present in FinFET diodes, then device density is improved, but active area for current production decreases
Solution Approach 1:
Multiple discrete fin structures are merged in function to collectively provide the total active area required for adequate diode efficiency. While spatially separated by dielectric material, the fins work together as a unified current-generating structure, combining their individual active areas to overcome the limitation of reduced active area per fin
3Productivity
If gate structures are made inactive, then current production is improved, but device complexity increases
Solution Approach 1:
The gate structures are extracted from their active transistor-control function and repurposed as purely structural elements that define the fin geometry and provide electrical isolation between adjacent fins. This extraction of the control function allows the diode to operate with optimized current production while the gate structures remain as simplified passive components
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 method increases the efficiency of FinFET diodes by optimizing the active area and current production, achieving higher efficiency compared to conventional FinFET diodes, as demonstrated by computer simulations.
Implementation Method 1
two oppositely doped regions (440 and 450) respectively formed upon the fin structures (410 and 420)... producing higher efficiency by mitigating the degradation problem in the conventional FinFET diodes due to the reduced active area for the presence of fin structures
Data Source
AI summary
Disclosed are methods to form a FinFET diode of high efficiency, designed to resolve the degradation problem with a conventional FinFET diode arising from reduced active area, and a method of fabrication. The FinFET diode has a doped substrate, two spaced-apart groups of substantially parallel, equally-spaced, elongated semiconductor fin structures, dielectric layers formed between the two groups and among the fin structures for insulation, a plurality of substantially equal-spaced and parallel elongated gate structures perpendicularly traversing both groups of the fin structures, and two groups of semiconductor strips respectively formed lengthwise upon the two groups of the fin structures. The two groups of semiconductor strips are doped to have opposite conductivity types, p-type and n-type. The FinFET diode further has metal contacts formed upon the semiconductor strips. In an embodiment, the semiconductor strips may be integrally formed with the fin structures by epitaxial growth and in-situ doped.