Asymmetric Guard Ring Contacts for Tiled Radiation Detectors
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Solution Overview
Problem
Tiled radiation imaging detectors using room temperature semiconductors face non-uniformity and artifacts at the edges due to higher leakage current and electric field distortion, leading to undesirable dead pixels and reduced image quality, which conventional guard rings cannot fully mitigate without creating inactive spatial regions.
Innovation Solution
Asymmetrically positioning guard ring contact pads with respect to the symmetry axes of the detector, allowing them to be situated in place of signal pads at the outermost circumference and connected to the guard ring, thereby eliminating the formation of clusters of dead pixels and enabling tile rotation during assembly without creating dead pixel clusters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a co-planar guard ring is used to reduce electric field distortion and collect leakage current, then peripheral pixel performance is improved, but inactive spatial regions (dead pixels) are created
Solution Approach 1:
The guard ring contact pads are positioned asymmetrically with respect to the symmetry axes of the detector, specifically offset from the corners of the pixel array. This asymmetric positioning prevents the formation of dead pixel clusters at tile boundaries while still providing effective guard ring functionality for collecting leakage current and reducing electric field distortion.
2Reliability
If guard ring contact pads are positioned at the outermost circumference to improve edge pixel behavior, then electric field distortion is reduced, but dead pixels are created at the edges
Solution Approach 1:
The guard ring contact pads are positioned locally at specific locations along the outermost circumference of the pixel array, rather than uniformly distributed. This localized positioning provides targeted protection against electric field distortion and leakage current collection while minimizing the total number of dead pixels created.
3Ease of manufacture
If symmetric guard ring contacts are used, then manufacturing is simplified, but dead pixel clusters form at tile boundaries
Solution Approach 1:
The guard ring contact pads are positioned asymmetrically with respect to the symmetry axes of the detector, specifically offset from the corners of the pixel array. This asymmetric positioning prevents the formation of dead pixel clusters at tile boundaries while still providing effective guard ring functionality for collecting leakage current and reducing electric field distortion.
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 configuration reduces the need for error correction and minimizes inactive spatial regions, enhancing the reliability and assembly efficiency of the detector while maintaining image quality by preventing the formation of dead pixel clusters, thus improving the detector's performance and manufacturing efficiency.
Implementation Method 1
direct conversion compound semiconductor layer configured to convert high energy radiation photons into an electric current
Implementation Method 2
the side wall leakage current is collected by the guard ring
Data Source
AI summary
According to an embodiment, a device comprises a direct conversion compound semiconductor layer configured to convert high energy radiation photons into an electric current, the direct conversion compound semiconductor layer comprising: a pixel array positioned in the direct conversion compound semiconductor layer, including pixels located at an outermost circumference, wherein the pixels comprise signal pads; a guard ring encircling the pixel array, wherein the pixels at the outermost circumference are closest to the guard ring; guard ring contact pads, wherein the guard ring contact pads are situated in place of some of the pixel signal pads at the outermost circumference and connected to the guard ring; wherein the guard ring contact pads are further situated asymmetrically with respect to a symmetry x-axis and a symmetry y-axis of the direct conversion compound semiconductor layer. Other embodiments relates to a detector comprising an array of tiles according to the device, and an imaging system comprising: an x-ray source and the detector.