Oxide Semiconductor Transparent Electrode Overlap Aperture Ratio
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Solution Overview
Problem
Current display devices face challenges in achieving high aperture ratios while maintaining low manufacturing costs, especially in mobile electronic devices, where increased definition leads to decreased pixel aperture ratios and increased power consumption.
Innovation Solution
A semiconductor device with a TFT substrate is developed, featuring a gate electrode, first and second transparent electrodes, an oxide semiconductor layer, and source/drain electrodes, where the oxide semiconductor layer and second transparent electrode are formed from the same oxide film, with overlapping structures to increase aperture ratio without decreasing luminance, and a simplified manufacturing process is employed using an In-Ga-Zn-O based semiconductor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the definition of liquid crystal display devices is increased, then the display quality is improved, but the pixel aperture ratio decreases
Solution Approach 1:
The invention forms the second transparent electrode and oxide semiconductor layer from the same oxide film in a planar configuration, then utilizes vertical stacking (overlap in the thickness direction) to create capacitance. This dimensional transition from planar to vertical arrangement allows the storage capacitor to occupy less lateral space, thereby maintaining high aperture ratio while supporting high definition displays.
2Illumination intensity
If the aperture ratio of liquid crystal display devices is increased, then the display brightness is improved, but the power dissipation increases
Solution Approach 1:
The invention changes the material parameter by using an oxide semiconductor film with higher carrier mobility than conventional amorphous silicon. This parameter change enables the TFT to operate more efficiently with lower power consumption, allowing the display to maintain high brightness (high aperture ratio) without proportionally increasing power dissipation.
3Area of stationary object
If oxide semiconductor TFTs are used to reduce TFT size, then the aperture ratio is improved, but the manufacturing process complexity increases
Solution Approach 1:
The invention merges the formation of the second transparent electrode and the oxide semiconductor layer into a single step by forming both from the same oxide film. This consolidation reduces the number of manufacturing steps and simplifies the process, counteracting the potential complexity increase from using oxide semiconductor materials to achieve smaller TFT sizes.
4Area of stationary object
If the combined area of TFT and storage capacitor is decreased, then the aperture ratio is improved, but the capacitance value may be reduced
Solution Approach 1:
The invention transitions the storage capacitor structure from a lateral arrangement to a vertical stacked arrangement, where the second transparent electrode overlaps with the first transparent electrode in the thickness direction. This dimensional change allows the capacitor to maintain sufficient capacitance value while occupying minimal lateral area, enabling high aperture ratio without sacrificing capacitance.
Data Source
AI summary
This semiconductor device (100A) includes: a substrate (1); a gate electrode (3) and a first transparent electrode (2) which are formed on the substrate (1); a first insulating layer (4) formed over the gate electrode (3) and the first transparent electrode (2); an oxide semiconductor layer (5) formed on the first insulating layer (4); source and drain electrodes (6s, 6d) electrically connected to the oxide semiconductor layer (5); and a second transparent electrode (7) electrically connected to the drain electrode (6d). At least a portion of the first transparent electrode (2) overlaps with the second transparent electrode (7) with the first insulating layer (4) interposed between them, and the oxide semiconductor layer (5) and the second transparent electrode (7) are formed out of the same oxide film.