TFT Substrate Fluorine Layer for Uniform a-IGZO Resistance
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Solution Overview
Problem
The specific resistance of signal electrodes in thin film transistor substrates treated with Argon plasma is not sufficiently reduced and lacks uniformity, making it difficult to apply plasma treatment on larger substrates when using amorphous indium-gallium-zinc oxide (a-IGZO) semiconductor layers.
Innovation Solution
Incorporating a fluorine deposition layer and a hydrogen doped layer in the source and drain electrodes, treated with fluorine or helium plasma, to increase electron carrier concentration and achieve uniform specific resistance, with the fluorine deposition layer closer to the surface than the hydrogen doped layer, and further treating with helium plasma for enhanced uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Argon plasma treatment is applied to a-IGZO to form source and drain electrodes, then the specific resistance decreases to a certain level, but the specific resistance does not sufficiently decrease below a certain level and lacks uniformity
Solution Approach 1:
The patent changes the plasma treatment parameters by switching from Argon plasma to Fluorine plasma, which fundamentally alters the chemical interaction with a-IGZO. Fluorine plasma introduces fluorine atoms that dope the a-IGZO, significantly reducing specific resistance below the achievable level with Argon plasma alone.
Solution Approach 2:
The patent introduces Fluorine as an intermediary substance through fluorine plasma treatment. This intermediary (fluorine) acts as a dopant that mediates the electrical properties of a-IGZO, enabling sufficient reduction in specific resistance and improving uniformity across the electrode surface.
2Reliability
If plasma treatment is applied to reduce specific resistance, then conductivity improves, but uniformity of specific resistance across the surface deteriorates
Solution Approach 1:
The patent changes the plasma chemistry from inert Argon to reactive Fluorine, which fundamentally alters how the plasma interacts with a-IGZO. Fluorine plasma provides both conductivity enhancement through doping and improved uniformity due to the reactive nature of fluorine atoms that distribute more evenly across the surface.
Solution Approach 2:
The patent creates a composite structure where fluorine-doped a-IGZO forms the source and drain electrodes. This composite material approach combines the semiconductor properties of a-IGZO with the dopant effects of fluorine, achieving both high conductivity and uniformity.
3Ease of manufacture
If Ar plasma treatment is used on a-IGZO, then conductive regions are formed, but it is difficult to apply the plasma treatment on substrates having relatively large area due to non-uniform specific resistance
Solution Approach 1:
The patent changes the plasma treatment approach from Argon to Fluorine plasma, which enables uniform treatment across large substrate areas. Fluorine's reactive nature allows for more consistent doping and specific resistance reduction over extended surfaces, making large-area manufacturing feasible.
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 approach effectively reduces the specific resistance of the signal electrodes and improves their uniformity, enhancing the conductivity of the TFT substrate by increasing electron carrier concentration and ensuring consistent performance across larger areas.
Implementation Method 1
treating the a-IGZO layer by fluorine plasma may form a fluorine deposition layer on the a-IGZO layer
Implementation Method 2
a fluorine deposition layer, a hydrogen doped layer or both a fluorine deposition layer and a hydrogen doped layer
Implementation Method 3
a portion of the a-IGZO treated by Argon (Ar) plasma is converted to a conductive member
Implementation Method 4
treating the source electrode and the drain electrode by helium plasma
Data Source
AI summary
A thin film transistor substrate includes a base substrate, an active pattern, a gate insulation pattern and a gate electrode. The active pattern is disposed on the base substrate. The active pattern includes a source electrode, a drain electrode, and a channel disposed between the source electrode and the drain electrode. The gate insulation pattern and the gate electrode overlap with the channel. The gate insulation pattern is disposed between the channel and the gate electrode. The source electrode and the drain electrode each include a fluorine deposition layer.