Storage Capacitor Hillock Prevention via Insulating Layer
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Solution Overview
Problem
Display devices face electrical short circuits due to hillocks formed on storage capacitors during thermal treatment, which can disrupt the electrical performance of the capacitors.
Innovation Solution
A display device design that includes a storage capacitor with a first and second storage electrode, where the second gate insulating layer is formed between the electrodes, conforming to the shape of hillocks on the first storage electrode, and a capping layer is used to prevent Al migration, thereby preventing electrical short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-specific resistance material is used to fabricate the storage capacitor, then electrical performance of the storage capacitor is improved, but hillocks are generated during thermal treatment causing electrical short circuit
Solution Approach 1:
An insulating layer is introduced as an intermediary between the first storage electrode and the second storage electrode. This insulating layer prevents direct contact between the electrodes even when hillocks form on the first storage electrode during thermal treatment, thereby eliminating the electrical short circuit problem while maintaining the use of low-specific resistance materials for good electrical performance.
2Reliability
If thermal treatment is performed on the storage capacitor, then electrical performance is improved, but hillocks are generated on the storage electrode
Solution Approach 1:
The insulating layer is formed on the first storage electrode before subsequent thermal treatment processes. This layer acts as a cushion that prevents the formation of hillocks during thermal treatment, maintaining the surface morphology of the storage electrode while still allowing the thermal treatment to improve electrical performance.
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 solution effectively prevents electrical short circuits and maintains the electrical performance of the storage capacitor, ensuring stable operation of the display device.
Implementation Method 1
forming hillocks on the first storage electrode by performing a heat treatment process
Implementation Method 2
The insulating layer is formed between the first storage electrode and the second storage electrode
Data Source
AI summary
A method of fabricating a display device including forming one or more thin-film transistors (“TFTs”) each configured to include an active layer, a gate insulating layer, a gate electrode, a source electrode, and a drain electrode on a substrate. A storage capacitor including a first storage electrode and a second storage electrode overlapping the first storage electrode with the gate insulating layer interposed there between is also formed on the substrate. A top surface of the first storage electrode may include hillocks and the gate insulating layer is formed between the first storage electrode and the second storage electrode to conform to the shape of the top surface of the first storage electrode with the hillocks.