Hydrogen Blocking Layer for X-ray Detector TFT Reliability

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Solution Overview

Problem

The degradation of thin-film transistors (TFTs) in digital X-ray detectors due to hydrogen penetration during the manufacturing process affects the performance of digital X-ray detectors, which is a challenge in maintaining the reliability and efficiency of these devices.

Innovation Solution

The implementation of a hydrogen blocking layer, typically made of indium tin oxide (ITO) or double metal layers including ITO, is applied on the TFTs and pad electrodes to prevent hydrogen penetration, enhancing the process efficiency and maintaining the electrical properties of the TFTs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the photodiode manufacturing process is performed, then the X-ray sensing capability is achieved, but hydrogen penetration occurs during the process

Engineering Contradiction:
ImproveX-ray sensing capabilityVSAvoidHydrogen penetration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The hydrogen blocking layer is formed in advance, before the photodiode manufacturing process that generates hydrogen. This preliminary protective measure is implemented proactively to prevent hydrogen penetration before it can occur during subsequent manufacturing steps. The blocking layer is positioned and configured to anticipate and counteract the hydrogen release that will happen during photodiode fabrication.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The hydrogen blocking layer serves as a protective intermediary barrier that is introduced into the structure to specifically counteract the harmful hydrogen penetration issue. This intermediary layer does not interfere with the photodiode's intended function but specifically addresses the hydrogen contamination problem by providing a diffusion barrier during the manufacturing process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If no hydrogen blocking layer is applied, then the manufacturing process is simpler, but the TFT performance degrades

Engineering Contradiction:
ImproveManufacturing process simplicityVSAvoidTFT performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The hydrogen blocking layer is implemented as a relatively simple intermediary component that can be integrated into existing manufacturing processes. While it adds one additional layer to the structure, the principle behind its formation follows conventional thin-film deposition techniques, making it easier to implement than the alternative of dealing with TFT performance degradation and its associated rework or yield loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 hydrogen blocking layer effectively prevents the degradation of TFTs, ensuring improved performance and reliability of digital X-ray detectors by blocking hydrogen ingress during the manufacturing process, thereby maintaining the electrical properties and efficiency of the devices.

Implementation Method 1

forming a hydrogen diffusion barrier layer that covers the entire substrate, wherein the hydrogen diffusion barrier layer is electrically conductive

Methodology Applied
Scientific EffectHydrogen diffusion barrier: Diffusion Barrier

Data Source

PatentEP3499574B1Substrate for digital x-ray detector, digital x-ray detector including the same and manufacturing method thereof
Publication Date: 2022.10.19 LG DISPLAY CO LTD
  • EP3499574B1 patent drawingFigure 1
  • EP3499574B1 patent drawingFigure 2
  • EP3499574B1 patent drawingFigure 3

AI summary

A substrate for a digital X-ray detector (1) configured to sense an X-ray signal, a detector (1) including the same, and a manufacturing method thereof. According to an embodiment of the present disclosure, the substrate for an X-ray detector (1) includes an interlayer dielectric layer (125) arranged on a thin film transistor (110, 115, 120), a first passivation layer (135) and a second passivation layer (165) arranged on the interlayer dielectric layer (125), and a hydrogen blocking layer (210, 220) arranged on at least one of the first passivation layer (135) and the second passivation layer (165) in a transistor region corresponding to the thin film transistor.