Dual-Active-Area Display Transistor for Threshold Voltage Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
During the aging process in display device manufacturing, a shift in threshold voltage of transistors can degrade their performance, leading to deteriorated display device performance and increased defects and yield reduction.
Innovation Solution
A display device design featuring a transistor with a dual active area structure, including a first and second active area, a gate insulating layer, and charge layers positioned at specific interfaces to shift the threshold voltage in opposite directions, effectively compensating for voltage shifts and minimizing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single active area transistor structure is used, then the manufacturing process is simple, but the threshold voltage shifts during aging process degrading transistor performance
Solution Approach 1:
The transistor is divided into a dual active area structure with first and second active areas, each having separate channel areas adjacent to source and drain regions. This segmentation allows independent charge layer formation in each active area, enabling threshold voltage compensation through opposite charges while maintaining manufacturing feasibility through systematic process steps.
Solution Approach 2:
Different charge layers are formed in different active areas with opposite charges (positive in first active area, negative in second active area, or vice versa). This local differentiation allows threshold voltage shifts to be compensated in opposite directions, stabilizing overall transistor performance during aging while maintaining a structured approach to manufacturing complexity.
2Reliability
If aging process is applied to prevent transistor characteristic changes, then transistor reliability is improved, but manufacturing process time and complexity increase
Solution Approach 1:
The dual active area structure with opposite charge layers is designed to inherently compensate for threshold voltage shifts during aging. By pre-configuring the transistor with this symmetric dual structure, the patent eliminates the need for additional aging process steps, thereby maintaining reliability improvement while reducing manufacturing time and process complexity.
3Reliability
If dual active area structure with charge layers is implemented, then threshold voltage stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The transistor is divided into a dual active area structure with first and second active areas, each having separate channel areas adjacent to source and drain regions. This segmentation allows independent charge layer formation in each active area, enabling threshold voltage compensation through opposite charges while maintaining manufacturing feasibility through systematic process steps.
Solution Approach 2:
The patent employs opposite charge layers with controlled charge densities and distributions in different active areas. By adjusting the charge parameters (positive in first active area, negative in second active area), the threshold voltage shifts are compensated in opposite directions, achieving stability without requiring extreme manufacturing precision.
Data Source
AI summary
A display device includes a transistor including an active layer including first and second active areas, where the first active area includes a first drain area, a source area, and a first channel area between the source area and the first drain area, and the second active area includes the source area, a second drain area, and a second channel area between the source area and the second drain area, a gate insulating layer on the active layer, first and second charge layers at an interface between the first channel area and the gate insulating layer and at an interface between the second channel area and the gate insulating layer, where the first charge layer is adjacent to the source area, and the second charge layer is adjacent to the first and second drain areas and has a charge opposite to a charge of a first charge layer.