Rounded Edge Active Patterns in Thin Film Transistors
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Solution Overview
Problem
Thin film transistors in organic light-emitting display apparatuses suffer from a 'hump phenomenon' due to angled edge portions, leading to increased leakage current and degraded cut-off properties, which cause random smudges on the panel.
Innovation Solution
A thin film semiconductor device with a substrate and an active pattern featuring rounded upper and lower edge portions, where the first and second gate insulation films expose and cover the rounded edges, and a gate electrode overlaps the active pattern, reducing electric field concentration and preventing the hump phenomenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an active pattern is formed by conventional patterning process, then the manufacturing process is simple, but the electric field is concentrated at the angled edge portion causing hump phenomenon and increased leakage current
Solution Approach 1:
The patent applies curvature by rounding the edge portions of the active pattern instead of having sharp angled edges. This is achieved through a multi-step patterning process that includes forming a semiconductor layer, applying a mask pattern, and performing controlled etching that creates rounded edges. The rounded edges prevent electric field concentration, thereby eliminating the hump phenomenon and improving cut-off properties without significantly complicating the overall manufacturing process.
2Ease of manufacture
If the active pattern has angled edge portions, then the patterning process is straightforward, but leakage current increases due to electric field concentration at the edges
Solution Approach 1:
The patent modifies the active pattern geometry by rounding the edge portions through a controlled patterning process. This involves forming a semiconductor layer, applying a mask with rounded corners, and performing etching that reproduces the rounded shape. The curved edges distribute the electric field more evenly, preventing the concentration that causes leakage current, while maintaining manufacturing feasibility through standard photolithography and etching techniques.
3Ease of manufacture
If conventional patterning is used to form the active pattern, then manufacturing cost is low, but random smudges occur on the panel due to parametric deviation
Solution Approach 1:
The patent introduces rounded edge portions in the active pattern through a modified patterning process that uses masks with rounded corners and controlled etching parameters. This geometric modification reduces parametric deviation by eliminating sharp angles that are sensitive to manufacturing variations. The rounded edges provide more consistent electrical characteristics across different devices, preventing random smudges on the panel while maintaining cost-effectiveness through standard manufacturing techniques.
Data Source
AI summary
An apparatus and a method of manufacturing a thin film semiconductor device having a thin film transistor with improved electrical properties in organic light-emitting display apparatus are described.