Stacked Oxide Thin-Film Transistor for Mobility and Interface Stability
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Solution Overview
Problem
Existing thin film transistors face challenges with mobility and stability due to defects formed during the etching process for source and drain electrodes, as well as interface defects between the channel layer and insulating layers.
Innovation Solution
A thin film transistor with a stack of multiple oxide layers, including a channel layer, a transition layer, and a first barrier layer, where the channel layer has the highest carrier mobility, and the transition and barrier layers have higher crystallization degrees and band gaps than the channel layer, enhancing protection and carrier confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single mask is used to form multiple oxide layers, then manufacturing complexity is reduced, but manufacturing precision may be compromised
Solution Approach 1:
The patent segments the oxide semiconductor layer into multiple functional layers (channel layer, transition layer, barrier layer) with different compositions and properties, each serving specific purposes. This segmentation allows precise control of carrier mobility and defect prevention while maintaining a simplified single-mask manufacturing process.
Solution Approach 2:
Different regions of the oxide semiconductor layer are assigned different local qualities: the channel layer has high carrier mobility for efficient transport, the transition layer provides gradual composition change to reduce interface defects, and the barrier layer has high crystallization degree to prevent carrier leakage. This local quality differentiation resolves the contradiction between manufacturing simplicity and precision.
2Reliability
If the channel layer has high carrier mobility, then transistor performance improves, but interface defects between channel layer and insulating layers increase
Solution Approach 1:
The transition layer acts as an intermediary between the channel layer and the barrier layer, providing a gradual composition transition that reduces interface defects. This intermediary layer has carrier mobility and band gap values between those of the channel and barrier layers, effectively mediating the interface properties to prevent defect formation while maintaining high transistor performance.
Solution Approach 2:
The patent changes key parameters (carrier mobility, band gap, crystallization degree) progressively across different layers. The channel layer has high carrier mobility for performance, while the barrier layer has high crystallization degree and large band gap to prevent defects. The transition layer provides gradual parameter changes to avoid abrupt interfaces that cause defects.
3Reliability
If the barrier layer has high crystallization degree, then carrier confinement improves, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functional requirements into a unified multi-layer oxide semiconductor structure that can be formed by a single mask process. The channel, transition, and barrier layers are combined in a sequential deposition process using one mask, reducing manufacturing complexity while achieving the desired carrier confinement through the high crystallization degree of the barrier layer.
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 proposed structure significantly increases the carrier mobility and stability of the thin film transistor by reducing defects and interface issues, while also simplifying the manufacturing process with the use of a single mask for forming the multiple oxide layers.
Implementation Method 1
the channel layer is a layer with a highest carrier mobility in the multiple oxide layers
Implementation Method 2
a crystallization degree of the first barrier layer and a crystallization degree of the transition layer are both greater than a crystallization degree of the channel layer
Implementation Method 3
a band gap of the first barrier layer and a band gap of the transition layer are both larger than a band gap of the channel layer
Data Source
AI summary
A thin film transistor, a manufacturing method thereof, an array substrate and an electronic device arc provided. The thin film transistor includes an active layer including multiple oxide layers which includes a channel layer, a transition layer and a first barrier layer, the channel layer is an layer with a highest carrier mobility, the channel layer is a crystalline or amorphous oxide layer, the transition layer is in direct contact with the channel layer, the first barrier layer is an outermost oxide layer, the first barrier layer and the transition layer are both crystalline oxide layers; a crystallization degree of the first barrier layer and a crystallization degree of the transition layer are greater than a crystallization degree of the channel layer, and a band gap of the first barrier layer and a band gap of the transition layer are larger than a band gap of the channel layer.