Graphene Barrier Layer for TFT Metal Diffusion Prevention
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Solution Overview
Problem
The use of oxide semiconductors in thin film transistors leads to issues with metal diffusion and the formation of projections due to bonding with oxygen, which deteriorates the transistor characteristics, especially when using traditional barrier layers like titanium.
Innovation Solution
A graphene-based barrier layer is introduced between the semiconductor layer and the source/drain electrodes, along with a capping layer made of graphene, to prevent metal diffusion and reduce foreign substance defects, enhancing adhesion and preventing oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional barrier layer (e.g., titanium) is used to prevent metal diffusion, then metal diffusion is prevented, but projections are formed due to oxygen bonding with the barrier layer material
Solution Approach 1:
The patent introduces an intermediary layer between the oxide semiconductor and the barrier layer. This intermediary layer acts as a mediator that prevents direct interaction between the barrier layer material and oxygen, thereby preventing projection formation while maintaining the barrier layer's metal diffusion prevention function. The intermediary layer is positioned specifically at the interface where oxygen bonding causes problems.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers with different materials: the oxide semiconductor layer, the intermediary layer, and the barrier layer. This composite material approach allows each layer to perform its specific function - the barrier layer prevents metal diffusion while the intermediary layer prevents oxygen bonding projections, resolving the contradiction between diffusion prevention and interface flatness.
2Reliability
If copper is used as wiring material to reduce resistance, then resistivity characteristics improve, but adhesion to glass substrate deteriorates and diffusion to insulating layers occurs
Solution Approach 1:
The patent uses a composite wiring structure with multiple layers: the copper wiring layer for low resistance, the barrier layer to prevent copper diffusion to insulating layers and substrate, and the intermediary layer to prevent projection formation. This composite material approach allows copper's excellent electrical properties to be utilized while compensating for its poor adhesion and high diffusion tendency through the additional functional layers.
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 graphene barrier layer effectively prevents metal diffusion and oxidation, maintaining the integrity of the thin film transistor characteristics and reducing defects, thereby improving the reliability of the thin film transistor and array panel.
Implementation Method 1
a barrier layer disposed between the semiconductor layer and the source electrode and between the semiconductor layer and the drain electrode, wherein the barrier layer comprises graphene
Implementation Method 2
there is a problem that a part of the constituent components of the oxide semiconductor is extracted due to a metal characteristic of bonding with oxygen
Data Source
AI summary
Provided is a thin film transistor and thin film transistor panel array. The thin film transistor includes: a substrate; a gate electrode disposed on the substrate; a semiconductor layer disposed on the substrate and partially overlapping with the gate electrode; a source electrode and a drain electrode spaced apart from each other with respect to a channel region of the semiconductor layer; an insulating layer disposed between the gate electrode and the semiconductor layer; and a barrier layer disposed between the semiconductor layer and the source electrode and between the semiconductor layer and the drain electrode, in which the barrier layer comprises graphene. An ohmic contact is provided based on the type of material used for the semiconductor layer.