Thin-Film Transistor Etch-Stopper Removal for Hump Phenomenon
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Solution Overview
Problem
The use of organic materials for the etch-stopper layer in etch-stopper thin-film transistors results in a 'hump phenomenon' in transistor characteristics, particularly in regions where current rapidly increases, which is critical for black display regions in organic EL displays.
Innovation Solution
A method involving the formation of an etch-stopper layer comprising organic materials, followed by dry etching and removal of the altered layer, with a passivation layer having a major component identical to the etch-stopper layer to reduce parasitic transistor effects and hump phenomenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an etch-stopper layer comprising organic materials is used, then the channel layer is protected from etching damage and manufacturing precision is improved, but hump phenomenon appears in transistor characteristics
Solution Approach 1:
The patent removes the problematic organic etch-stopper layer after it has served its protective function during manufacturing. This extraction eliminates the source of hump phenomenon while maintaining the benefits of etching protection during the manufacturing process.
Solution Approach 2:
The patent performs preliminary protective action by forming the organic etch-stopper layer before etching to protect the channel layer. This preliminary protection allows precise etching to create source/drain electrodes without damaging the channel, after which the protective layer is removed.
2Reliability
If the channel layer is made thinner to reduce parasitic resistance, then turn-on characteristics are improved, but the channel layer becomes more vulnerable to etching damage
Solution Approach 1:
The patent applies beforehand cushioning by forming the organic etch-stopper layer over the thin channel layer before etching. This cushioning layer protects the vulnerable thin channel from etching damage, enabling the use of thinner channels for better turn-on characteristics without sacrificing robustness during manufacturing.
3Ease of manufacture
If photolithography process is reduced to lower manufacturing cost, then ease of manufacture is improved, but manufacturing precision may be compromised
Solution Approach 1:
The organic etch-stopper layer serves as an intermediary that enables simplified manufacturing processes. By providing self-aligned protection, it allows for reduced photolithography steps while maintaining precise pattern definition, as the etch-stopper layer itself defines the protection boundaries without requiring additional masking steps.
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 results in thin-film transistors with improved transistor characteristics by reducing the hump phenomenon and enhancing reliability, especially in low gray scale regions of organic EL displays.
Implementation Method 1
forming a semiconductor layer patterned, by performing dry etching on the semiconductor film
Implementation Method 2
forming a passivation layer so as to contact the semiconductor layer in a region in which the altered layer has been removed
Data Source
AI summary
A method for manufacturing a thin-film transistor, includes: preparing a substrate; forming a gate electrode above the substrate; forming a gate insulating layer above the gate electrode; forming a semiconductor film above the gate insulating layer; forming, above the semiconductor film, a protective layer comprising an organic material; forming a source electrode and a drain electrode above the protective layer; forming a semiconductor layer patterned, by performing dry etching on the semiconductor film; removing at least a portion of a region of an altered layer, the region contacting the semiconductor layer, the altered layer being a surface layer of the protective layer that is altered by the dry etching; and forming a passivation layer having a major component identical to a major component of the protective layer so as to contact the semiconductor layer in a region in which the altered layer has been removed.