Array Substrate Protective Stack Against TFT Hydrogen Damage

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Solution Overview

Problem

The semiconductor layer of thin film transistors on array substrates is adversely affected in hydrogen environments, leading to performance issues in photodiode manufacturing for display and medical applications.

Innovation Solution

The implementation of a stacked structure with a first inorganic protective layer, an organic hydrogen-stable protective layer, and a second inorganic protective layer between the thin film transistor and photodiode, along with a transparent conductive layer, to prevent hydrogen diffusion and contamination, enhancing the reliability of the array substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photodiode manufacturing is performed in a hydrogen environment (silicon hydride or hydrogen atmosphere), then photodiode deposition quality is improved, but the semiconductor layer of thin film transistors is adversely affected

Engineering Contradiction:

Improvephotodiode deposition qualityVSAvoidthin film transistor performance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The protective structure is divided into three distinct layers: first inorganic protective layer, organic protective layer, and second inorganic protective layer. Each layer serves a specific function in blocking hydrogen diffusion while maintaining structural integrity, allowing the photodiode to be manufactured in hydrogen environment without damaging the TFT semiconductor layer.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stacked protective layers act as an intermediary barrier between the hydrogen environment (where photodiode is deposited) and the semiconductor layer (which must be protected). This intermediary structure allows the harmful hydrogen atmosphere to exist for photodiode manufacturing while preventing hydrogen from reaching and damaging the semiconductor layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the orthographic projection of the photodiode overlaps with the thin film transistor area, then device integration is improved, but hydrogen diffusion to the semiconductor layer increases

Engineering Contradiction:

Improvedevice integrationVSAvoidhydrogen diffusion to semiconductor layer

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The protective layers are strategically positioned and sized so that their orthographic projections cover both the thin film transistor and photodiode areas. The layers have different material properties and thicknesses optimized for their specific locations, providing enhanced protection to the semiconductor layer while allowing photodiode deposition in the hydrogen environment.

Inventive Principle:

Principle #3Local quality

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 hydrogen diffusion to the semiconductor layer, improves the reliability of the thin film transistor, and increases the signal-to-noise ratio for accurate detection, while maintaining the photodiode's performance and reducing dark current.

Implementation Method 1

an organic protective layer... between the thin film transistor and photodiode... to prevent hydrogen diffusion and contamination

Methodology Applied

Scientific EffectHydrogen diffusion barrier: Diffusion Barrier

Data Source

PatentUS12068355B2Array substrate, flat panel detector, and method for manufacturing array substrate

Publication Date: 2024.08.20 BOE TECHNOLOGY GROUP CO LTD

AI summary

An array substrate includes a substrate, the array substrate includes a display region and a detection region. And the detection region includes a thin film transistor located on the substrate and a photodiode located on one side of the thin film transistor away from the substrate, and the array substrate further includes a first inorganic protective layer, an organic protective layer and a second inorganic protective layer located between the thin film transistor and the photodiode. And the first inorganic protective layer, the organic protective layer and the second inorganic protective layer are stacked in sequence in a direction away from the substrate, and an orthographic projection of the photodiode on the substrate is within the range of the orthographic projection of the organic protective layer on the substrate.