Oxide Semiconductor Capacitor Vertical Stacking for OLED Charge Capacity
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Solution Overview
Problem
Current active matrix-type organic light emitting display devices require capacitors with insufficient charge capacity, which affects the stability and naturalness of the displayed images.
Innovation Solution
A capacitor structure is developed with a metal layer-insulating layer-oxide semiconductor layer-metal layer stacked through an opening in the insulating layer, enhancing charge capacity without increasing the capacitor's area, and including a thin film transistor and organic light emitting element connected via a passivation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacitor area is increased to improve charge capacity, then the charge capacity increases, but the light emitting region is reduced
Solution Approach 1:
The patent transitions from a planar capacitor structure to a three-dimensional stacked structure by forming multiple insulating layers and metal layers in vertical succession. The capacitor includes a first metal layer, first insulating layer, oxide semiconductor layer, second insulating layer, and second metal layer stacked vertically, with the second metal layer extending into an opening of the second insulating layer. This vertical stacking increases charge capacity without expanding the horizontal area occupied by the capacitor, thereby preserving the light emitting region.
2Quantity of substance
If a conventional capacitor structure is used, then the manufacturing process is simple, but the charge capacity is insufficient
Solution Approach 1:
The patent employs a composite layered structure combining different materials: metal layers (conductive), insulating layers (dielectric), and oxide semiconductor layers. This composite structure integrates multiple material properties to achieve enhanced charge capacity. The specific combination of conductive metal layers with high-k insulating layers and oxide semiconductor layers creates a capacitor with superior electrical characteristics compared to conventional single-material structures.
Solution Approach 2:
The capacitor structure implements a nested configuration where the second metal layer is formed within an opening of the second insulating layer, which itself is positioned above the oxide semiconductor layer. This nested arrangement allows the capacitor electrodes to extend vertically into the insulating layer, effectively increasing the electrode area and charge storage capacity without proportionally increasing the overall device footprint or manufacturing complexity.
Data Source
AI summary
A capacitor of an organic light emitting display device includes a first metal layer on a substrate, a first insulating layer on the first metal layer, an oxide semiconductor layer on the first insulating layer, the oxide semiconductor layer corresponding to the first metal layer, a second insulating layer on the first insulating layer, the second insulating layer including an opening exposing a portion of the oxide semiconductor layer, and a second metal layer on the second insulating layer and in the opening, the second metal layer being connected to the exposed portion of the oxide semiconductor layer.