Array Substrate Reflective Insulating Structure for Threshold Stability
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Solution Overview
Problem
The threshold voltage of transistors in display devices shifts positively over time due to repeated application of positive charges, leading to deterioration of transistor characteristics.
Innovation Solution
An array substrate design featuring a transistor configuration with a light reflective portion that includes overlapping and non-overlapping portions in the insulating film, reflecting light away from the semiconductor and gate electrodes to stabilize the threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional transistor structure is used without light reflective portions, then the device structure is simpler, but the threshold voltage shifts positively over time due to repeated application of positive charges, causing transistor characteristics to deteriorate
Solution Approach 1:
The insulating film is segmented into multiple regions: a first insulating film in the channel formation region and a second insulating film in the source and drain regions. The second insulating film further includes a light reflective portion and a non-light-reflective portion, creating functional segmentation within the insulating structure to address different operational requirements in different regions.
Solution Approach 2:
Different portions of the insulating film are assigned different properties: the first insulating film provides standard insulation in the channel region, while the second insulating film provides both insulation and light reflection in the source and drain regions. This local differentiation of properties allows the structure to prevent threshold voltage shift without requiring complete structural redesign.
2Reliability
If a light reflective portion is added to reflect light away from the semiconductor and gate electrodes, then the threshold voltage stability improves, but the manufacturing process becomes more complex
Solution Approach 1:
The light reflective function is merged with the existing second insulating film structure rather than being implemented as a separate component. The second insulating film simultaneously provides electrical insulation and optical reflection functions, reducing the need for additional separate structures and simplifying the overall manufacturing process.
Solution Approach 2:
The second insulating film is designed to perform multiple functions: electrical insulation between the semiconductor portion and electrodes, and optical reflection to prevent light-induced threshold voltage shifts. This multi-functionality reduces the number of separate components needed and streamlines the manufacturing process.
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 design effectively prevents transistor characteristics from deteriorating by shifting the threshold voltage in a negative direction, enhancing the stability and longevity of the transistors.
Implementation Method 1
a light reflective portion provided on an upper-layer side of the second insulating film... the non-overlapping portion includes a first filling portion that fills the first recessed portion
Data Source
AI summary
An array substrate includes a transistor including a first electrode a semiconductor portion, a second electrode and a third electrode, a first insulating film provided on an upper-layer side of the first electrode and on a lower layer side of the semiconductor portion, a second insulating film provided on an upper-layer side of the second electrode and the third electrode, and a light reflective portion provided on an upper-layer side of the second insulating film, in which the second insulating film is provided with a first recessed portion at a position overlapping none of the first electrode and the semiconductor portion, the light reflective portion includes an overlapping portion overlapping the first electrode and the semiconductor portion and a non-overlapping portion overlapping none of the first electrode and the semiconductor portion, and the non-overlapping portion includes a first filling portion that fills the first recessed portion.