Radiation Detector Sidewall Coating for Edge Pixel Reliability

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Solution Overview

Problem

Existing radiation detectors, particularly those made of cadmium zinc telluride (CZT), face challenges with edge pixel detectors exhibiting poor performance and reliability due to defects from cutting and surface contamination, which affect image quality, especially in CT reconstruction.

Innovation Solution

A protective coating is applied over the sidewalls of radiation sensors using a conformal deposition process after assembly into a detector unit, enhancing the reliability and performance of edge pixel detectors by mitigating defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If edge pixel detectors are used in radiation detectors, then the detector coverage and resolution are improved, but defects from cutting and surface contamination increase, reducing reliability

Engineering Contradiction:

Improvedetector resolutionVSAvoidedge pixel detector reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

A protective coating is applied to the sidewalls of the radiation sensor before assembly into the final detector structure. This coating is deposited in advance to prevent surface contamination and protect against defects that would otherwise occur during subsequent handling, cutting, and assembly processes. The coating acts as a preliminary protective measure that prevents rather than repairs damage.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

A thin film protective coating is deposited conformally over the sidewalls of the radiation sensor. This thin film provides protection against surface contamination and mechanical damage while maintaining the structural integrity and electrical properties of the underlying sensor material. The coating follows the contours of the sidewalls, providing uniform protection.

Inventive Principle:

Principle #30Flexible shells and thin films

2Reliability

If a protective coating is applied over sidewalls of radiation sensors, then reliability of edge pixel detectors is improved, but device complexity and manufacturing steps increase

Engineering Contradiction:

Improveedge pixel detector reliabilityVSAvoiddetector structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protective coating deposition is integrated into the existing manufacturing process flow, combining the protection function with the assembly process. Rather than adding a separate, complex protection system, the coating is deposited as part of the standard fabrication sequence, merging multiple functions into a unified process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The mechanical approach of protecting sensors through careful handling and packaging is replaced with a chemical/physical vapor deposition process. Instead of relying on mechanical protection methods that add structural complexity, a conformal coating process is used that provides protection through a thin deposited layer, substituting mechanical complexity with a more streamlined deposition process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If conformal deposition process is used to apply protective coating, then coating uniformity over sidewalls is improved, but deposition time and manufacturing complexity increase

Engineering Contradiction:

Improvecoating uniformityVSAvoiddeposition time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The conformal deposition process applies coating material slightly in excess of the minimum required thickness, ensuring complete and uniform coverage of the sidewalls. This partial excess action guarantees that no areas are under-coated, achieving uniformity even if it requires slightly more material and time than the absolute minimum would demand.

Inventive Principle:

Principle #16Partial or excessive action

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 protective coating improves the reliability and performance of edge pixel detectors, reducing defects and maintaining image quality in radiation detection systems.

Implementation Method 1

A protective coating is applied over the sidewalls of radiation sensors using a conformal deposition process

Methodology Applied

Scientific EffectConformal deposition: Deposition (physical)

Data Source

PatentUS20250284012A1Radiation detector structures with sidewall coating and methods of fabrication thereof

Publication Date: 2025.09.11 REDLEN TECH

AI summary

A detector structure includes a carrier board, at least one application specific integrated circuit (ASIC) located over the carrier board, the at least one ASIC including signal processing channel circuitry, at least one radiation sensor located over a front side of the at least one ASIC, and a protective coating located over sidewalls of the at least one radiation sensor and over at least a portion of the carrier board and the at least one ASIC. In various embodiments, the detector structure including the at least one radiation sensor is assembled prior to depositing a protective coating layer over portions of the detector structure including the sidewalls of the at least one radiation sensor.