Display Device Light Blocking Layer Non-Overlap Region
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Solution Overview
Problem
The existing display devices using oxide transistors face unstable negative bias thermal illumination stress (NBTiS) characteristics, and the proposed light blocking layer scheme to address this issue causes shorts between the light blocking layer and the source/drain metal layer due to over-etching and interlayer structure issues.
Innovation Solution
A display device structure is implemented with a light blocking layer having a non-overlap region where the source/drain metal layer does not overlap the light blocking layer, and a semiconductor layer is positioned on a buffer layer with an insulating layer in between, preventing electrical contact and thus avoiding shorts during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light blocking layer is inserted into the lower part of the oxide transistor to improve NBTiS characteristics, then the stability of the transistor is improved, but a short occurs between the light blocking layer and the source/drain metal layer due to over-etching and interlayer structure issues
Solution Approach 1:
An insulating layer is introduced as an intermediary between the light blocking layer and the source/drain metal layer. This insulating layer acts as a mediator that prevents direct electrical contact (short) between the two conductive layers while allowing the light blocking layer to maintain its position for improving NBTiS characteristics. The insulating layer resolves the harmful interaction without compromising the beneficial function of the light blocking layer.
Solution Approach 2:
The structure is segmented into distinct functional layers with clear boundaries: the light blocking layer, the insulating layer, and the source/drain metal layer are separated into discrete segments. This segmentation prevents the merging of conductive paths that would cause shorts, while maintaining the functional integrity of each layer. The insulating layer segment specifically divides the electrical domains to prevent harmful interactions.
2Reliability
If the source/drain metal layer overlaps the light blocking layer to ensure proper electrical connection, then electrical connectivity is achieved, but over-etching causes a short between the layers
Solution Approach 1:
The insulating layer serves as a protective intermediary that allows the source/drain metal layer to overlap the light blocking layer region without causing shorts. Even if etching processes are not perfectly precise, the insulating layer provides a buffer that prevents direct contact between conductive layers, thereby decoupling the electrical connectivity requirement from the etching precision requirement.
Solution Approach 2:
The insulating layer is deposited beforehand to create a cushioning barrier between the light blocking layer and the source/drain metal layer. This prior cushioning protects against potential shorts that might occur due to etching variations, providing a safety margin that compensates for manufacturing precision limitations.
3Area of stationary object
If the light blocking layer and source/drain metal layer are positioned to overlap for structural compactness, then device area is reduced, but shorts occur due to interlayer structure issues
Solution Approach 1:
The insulating layer enables the overlapping configuration by acting as a mediator that prevents electrical shorting between the light blocking layer and source/drain metal layer. This allows the device to maintain a compact area with overlapping layers while the insulating layer ensures electrical isolation, resolving the conflict between compactness and short prevention.
Data Source
AI summary
Provided are a display device and a method of manufacturing the same. A display device includes: a light blocking layer on a first substrate, a buffer layer on the light blocking layer, a semiconductor layer on the buffer layer, an insulating layer on the semiconductor layer, and a source/drain metal layer positioned on the insulating layer, the source/drain metal layer including a non-overlap region that does not overlap the light blocking layer.