Photo Detection Element P/N Laminated Guard Ring Electric Field Relaxation
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Solution Overview
Problem
Current photo detection elements face challenges in enhancing photon detective efficiency, particularly due to issues with electric field concentration and curvature design affecting avalanche multiplication and dark current suppression.
Innovation Solution
The photo detection element incorporates a P/N laminated guard ring structure with specific conductivity types and curvature radii to optimize electric field distribution and carrier multiplication, improving photon detective efficiency by 8.6% compared to standard designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard guard ring structure is used, then the device complexity is low, but the photon detective efficiency is insufficient
Solution Approach 1:
The guard ring structure is segmented into multiple regions with alternating conductivity types (first conductivity type and second conductivity type) arranged in a laminated pattern. This segmentation allows different regions to perform specialized functions: some regions focus on electric field relaxation while others optimize avalanche multiplication, thereby improving photon detection efficiency without requiring a complete redesign of the entire guard ring structure.
Solution Approach 2:
Different regions of the guard ring are assigned different conductivity types and curvature radii to create local variations in electric field distribution. The first conductivity type regions are optimized for one function while the second conductivity type regions are optimized for another function, allowing each local area to contribute optimally to the overall photon detection performance.
2Measurement precision
If the curvature radius is reduced to improve detection precision, then the electric field concentration increases, but this causes after-pulse noise
Solution Approach 1:
The guard ring is divided into multiple segments with different curvature radii. Some segments have smaller curvature radii to provide sharp electric field termination and improve detection precision, while other segments have larger curvature radii to distribute the electric field more gently and reduce after-pulse noise. This segmented approach allows both contradictory requirements to be satisfied in different locations.
Solution Approach 2:
Different curvature radii are assigned to different regions of the guard ring based on their specific functional requirements. Regions where sharp field termination is needed have smaller curvature radii, while regions where field distribution is critical have larger curvature radii. This local optimization resolves the contradiction between detection precision and after-pulse noise suppression.
3Reliability
If the electric field is concentrated to enhance avalanche multiplication, then the photon detective efficiency improves, but the dark current increases
Solution Approach 1:
The guard ring structure is segmented into regions with alternating conductivity types, creating a laminated pattern that distributes the electric field in a controlled manner. This segmentation allows the electric field to be concentrated in specific avalanche multiplication regions to improve photon detection efficiency, while adjacent regions with different conductivity types provide field relaxation paths that suppress dark current generation.
Solution Approach 2:
The alternating conductivity type regions act as intermediaries that mediate between the need for electric field concentration and dark current suppression. The first conductivity type regions facilitate avalanche multiplication by concentrating the field, while the second conductivity type regions serve as intermediary zones that relax the field and provide alternative carrier paths, thereby reducing dark current.
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 P/N laminated guard ring structure enhances photon detective efficiency by effectively relaxing electric field concentrations and reducing after-pulse noise, achieving improved sensitivity and uniformity in photo detection.
Implementation Method 1
a third region of the first conductivity type provided between the first region and the second region, a fourth region of the second conductivity type provided so as to surround a periphery of the second region
Implementation Method 2
improving photon detective efficiency by 8.6% compared to standard designs
Implementation Method 3
incident light incident from above the second region 113 is subjected to photoelectric conversion in the silicon substrate 101
Data Source
AI summary
In one embodiment, a photo detection element includes a first region of a first conductivity type, a second region of a second conductivity type, a third region of the first conductivity type provided between the first region and the second region, a fourth region of the second conductivity type provided so as to surround a periphery of the second region, in a direction crossing with a direction from the first region toward the second region, and a fifth region of the first conductivity type provided between the first region and the fourth region.