SiNx Passivation Layer for Oxide TFT Hydrogen Diffusion Barrier
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Solution Overview
Problem
Oxide TFT display panels face issues with hydrogen atoms from passivation layers or gate insulating films reacting with oxide active layers, leading to conductivity and compromising electrical properties, and existing methods for forming passivation layers are time-consuming and difficult due to etching challenges and low deposition rates.
Innovation Solution
A TFT display panel with a passivation layer made of silicon nitride (SiNx) is used, which minimizes hydrogen content to prevent reaction with oxide active layers, and a dual-layer gate insulating film structure with different SiNx layers is employed to enhance electrical properties and reduce fabrication time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a passivation layer is formed as an oxide layer, then the difficulty of etching is reduced, but the deposition time increases due to low deposition rate
Solution Approach 1:
The passivation layer is formed as a composite structure comprising a first inorganic layer (oxide semiconductor) and a second inorganic layer (nitride or oxynitride). This composite structure combines the etching ease of oxide materials with the low hydrogen content of nitride materials, resolving the contradiction between etching ease and deposition time by leveraging the complementary properties of different materials in a layered configuration.
2Reliability
If the passivation layer is made as a double layer including oxide and nitride, then the hydrogen content is reduced, but the fabrication time and complexity increase
Solution Approach 1:
The passivation layer uses a composite structure where a first inorganic layer (oxide semiconductor) is combined with a second inorganic layer (nitride or oxynitride). This composite approach reduces hydrogen content while maintaining fabrication efficiency, as the nitride layer can be deposited using standard PECVD processes without significantly increasing overall fabrication time.
3Ease of manufacture
If hydrogen atoms are present in the passivation layer or gate insulating film, then the deposition process is simplified, but the oxide active layer becomes conductive due to hydrogen reaction
Solution Approach 1:
The nitride or oxynitride layer acts as an intermediary barrier between the hydrogen-containing gate insulating film and the oxide active layer. This intermediate layer prevents hydrogen atoms from migrating into the oxide active layer, thereby maintaining its insulating properties while allowing the use of hydrogen-containing materials in the gate insulating film for simplified deposition.
4Device complexity
If a single-layer passivation structure is used, then the fabrication process is simplified, but the electrical properties are compromised due to hydrogen content
Solution Approach 1:
The passivation layer is structured as a composite of a first inorganic layer (oxide semiconductor) and a second inorganic layer (nitride or oxynitride). This composite structure maintains relatively simple fabrication processes while significantly improving electrical stability by reducing hydrogen content, thus resolving the contradiction between structural simplicity and electrical reliability.
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 SiNx passivation layer and dual-layer gate insulating film structure improve the stability and electrical properties of the TFT display panel, reducing hydrogen interaction with oxide active layers and facilitating faster fabrication without compromising performance.
Implementation Method 1
If the passivation layer or the gate insulating film contains hydrogen atoms, the hydrogen atoms may move to the oxide active layer patterns so as to react with the oxide active layer patterns. Accordingly, the oxide active layer patterns may become conductive
Implementation Method 2
an upper gate insulating film formed on the lower gate insulating film and made of second SiNx, wherein the second SiNx contains a smaller amount of hydrogen than the first SiNx
Data Source
AI summary
Provided are a thin-film transistor (TFT) display panel having improved electrical properties that can be fabricated time-effectively and a method of fabricating the TFT display panel. The TFT display panel includes: gate wirings which are formed on an insulating substrate; oxide active layer patterns which are formed on the gate wirings; data wirings which are formed on the oxide active layer patterns to cross the gate wirings; a passivation layer which is formed on the oxide active layer patterns and the data wirings and is made of silicon nitride (SiNx); and a pixel electrode which is formed on the passivation layer.