Copper Nitride Thin-Film Transistor Structure Against Copper Diffusion
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Solution Overview
Problem
The oxidation or diffusion of copper in thin film transistors used in display panels leads to unstable electrical characteristics, affecting the display quality.
Innovation Solution
A manufacturing method for thin film transistors that includes forming a copper nitride layer as a covering layer or barrier layer on the copper conductive layers to prevent oxidation and diffusion, improving the electrical characteristics and reliability by preventing edge chamfer formation and reducing holes or cracks during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper is used as the material of conductive lines or electrodes to enhance carrier mobility, then the electrical conductivity is improved, but copper oxidation or diffusion occurs causing electrical characteristics to become unstable
Solution Approach 1:
A copper nitride layer is introduced as an intermediary barrier between the copper conductive layer and the external environment. This intermediate layer prevents direct contact between copper and oxidizing agents, thereby eliminating the harmful oxidation and diffusion effects while preserving copper's high conductivity benefits
Solution Approach 2:
The conductive structure is designed as a composite material system consisting of multiple layers: copper layer (for conductivity), copper nitride layer (for oxidation resistance), and optional additional barrier layers. This composite structure combines the advantages of different materials to achieve both high conductivity and high stability
2Reliability
If copper is used as the material of conductive lines or electrodes, then the carrier mobility is enhanced, but the manufacturing process becomes more complex due to additional barrier and covering layers
Solution Approach 1:
The copper nitride layer serves multiple functions simultaneously: it acts as a diffusion barrier, an oxidation prevention layer, and a protective covering layer. By consolidating multiple protective functions into a single layer, the overall structural complexity is reduced compared to using multiple separate barrier layers
Solution Approach 2:
The invention changes the chemical state of the copper surface by forming copper nitride through nitridation treatment. This parameter change (from metallic copper to copper nitride) transforms the surface properties to provide inherent protection against oxidation and diffusion, simplifying the need for additional complex protective structures
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 copper nitride layer effectively mitigates copper oxidation and diffusion, enhancing the stability and reliability of thin film transistors by maintaining consistent electrical characteristics and reducing manufacturing defects.
Implementation Method 1
the copper nitride layer is formed above, below or on the side surface of the copper layer of the source and drain as the covering layer, the barrier layer or the sidewall protection layer, which can mitigate the oxidation and diffusion of copper
Implementation Method 2
performing a nitridation treatment, the nitridation treatment forms a covering layer on an upper surface of the first conductive layer, the covering layer includes copper nitride
Data Source
AI summary
A thin film transistor includes a substrate, a gate, a gate insulating layer, a semiconductor layer, a first conductive layer, a covering layer and a sidewall protection layer. The gate is disposed on the substrate, the gate insulating layer is disposed on the gate, and the semiconductor layer is disposed on the gate insulating layer. The first conductive layer is disposed on the semiconductor layer, and the first conductive layer includes copper. The covering layer is disposed on an upper surface of the first conductive layer, and the covering layer includes copper nitride. The sidewall protection layer is disposed on a side surface of the first conductive layer, and the sidewall protection layer includes copper nitride.