Oxide Thin-Film Transistor Active Layer for Oxygen Isolation

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Solution Overview

Problem

The reliability of the active layer in multilayer oxide thin film transistors is poor, affecting the display effect due to oxygen diffusion and oxidation of source-drain metal layers during high temperature processes.

Innovation Solution

A metal oxide active layer is designed with a carrier transport layer and a carrier isolation layer, where the carrier isolation layer covers the lateral surface of the carrier transport layer, reducing oxygen diffusion and oxidation, and a via hole or blind hole is defined in the carrier isolation layer to enhance electrical coupling and reduce resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a multilayer oxide thin film transistor is designed with multiple high mobility and high impedance layers to improve mobility and stability, then the carrier transport performance is improved, but the reliability of the active layer deteriorates due to oxygen diffusion and oxidation during high temperature processes

Engineering Contradiction:

Improveactive layer reliabilityVSAvoidoxygen diffusion and oxidation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A carrier isolation layer made of metal oxide is introduced between the source-drain metal layer and the carrier transport layer. This intermediary layer prevents oxygen from the source-drain metal layer from diffusing into the carrier transport layer during high temperature processes, thereby resolving the oxidation problem while maintaining the multilayer structure's carrier transport performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The active layer is designed as a composite structure with a carrier transport layer (amorphous metal oxide) and a carrier isolation layer (crystalline metal oxide). The combination of different material states and properties creates a structure that simultaneously achieves high carrier mobility in the transport layer and oxygen barrier functionality in the isolation layer

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If the carrier isolation layer completely covers the carrier transport layer to prevent oxygen diffusion, then oxidation resistance is improved, but electrical coupling between source-drain metal layer and carrier transport layer deteriorates due to increased resistance

Engineering Contradiction:

Improveoxidation resistanceVSAvoidelectrical coupling

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The carrier isolation layer is segmented by creating via holes or blind holes through it. This segmentation allows selective regions where electrical coupling occurs (through the holes) while maintaining oxygen barrier functionality in the remaining covered areas, thus resolving the contradiction between isolation and conduction

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The carrier isolation layer exhibits different properties in different regions: in the covered areas it provides oxygen barrier protection, while in the via hole/blind hole regions it allows electrical coupling. This local differentiation of function resolves the contradiction between preventing oxidation and maintaining electrical connectivity

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 design improves the reliability of the oxide thin film transistor by reducing oxygen diffusion and oxidation, thereby maintaining structural integrity and enhancing carrier transport efficiency.

Implementation Method 1

reducing oxygen diffusion and oxidation

Methodology Applied

Scientific EffectOxygen diffusion: Diffusion

Implementation Method 2

reducing oxygen diffusion and oxidation

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 3

enhance electrical coupling

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS20250098225A1Oxide thin film transistor, method for manufacturing the same and display device

Publication Date: 2025.03.20 BOE TECHNOLOGY GROUP CO LTD

AI summary

An oxide thin film transistor includes: a gate electrode, a metal oxide active layer and a source-drain metal layer, which are on a base substrate. The metal oxide active layer includes a first metal oxide layer and a second metal oxide layer stacked on the first metal oxide layer in a direction away from the base substrate; the first metal oxide layer is a carrier transport layer; the second metal oxide layer is a carrier isolation layer; an electron transfer rate of the carrier transport layer is greater than an electron transfer rate of the carrier isolation layer. The first metal oxide layer includes a primary surface facing toward the base substrate and a primary surface away from the base substrate; the first metal oxide layer further includes a lateral surface around the primary surfaces; the second metal oxide layer covers the lateral surface of the first metal oxide layer.