Semiconductor Device with Light-Transmitting Electrodes
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving high aperture ratio, low power consumption, low wiring resistance, high transmittance, layout flexibility, and controlled threshold voltage, particularly in display devices where traditional thin film transistors using amorphous silicon limit performance.
Innovation Solution
A semiconductor device is designed with a pixel portion and driver circuit portion on a single substrate, utilizing light-transmitting materials for transistors and low resistance materials for driver circuits, along with a back gate structure to control threshold voltage, and employing oxide semiconductors like In-Ga-Zn-O for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a light-transmitting conductive film is used for gate, source, and drain electrodes to increase aperture ratio, then the aperture ratio increases, but the wiring resistance increases
Solution Approach 1:
The patent applies different material properties to different regions: light-transmitting conductive films (ITO, etc.) are used in pixel portions where aperture ratio is critical, while low-resistance metal films (Al, Mo, etc.) are used in driver circuit portions where wiring resistance must be minimized. This spatial differentiation of material quality resolves the contradiction between aperture ratio and wiring resistance.
Solution Approach 2:
The substrate is divided into functionally distinct regions: pixel portions requiring high aperture ratio and driver circuit portions requiring low wiring resistance. Each region is optimized with appropriate materials, allowing simultaneous achievement of high aperture ratio in display areas and low wiring resistance in circuit areas.
2Area of stationary object
If amorphous silicon is used as channel layer to enable larger substrate manufacturing, then larger substrates can be used, but field-effect mobility remains low
Solution Approach 1:
The patent changes the material parameter of the channel layer from conventional amorphous silicon to oxide semiconductor (In-Ga-Zn-O), which fundamentally alters the electrical properties to achieve high field-effect mobility while maintaining compatibility with large-area substrate manufacturing processes.
Data Source
AI summary
An object is to provide a semiconductor device in which characteristics of a driver circuit portion are improved while the aperture ratio of a pixel portion is increased. Alternatively, it is an object to provide a semiconductor device with low power consumption or to provide a semiconductor device in which the threshold voltage of a transistor can be controlled. The semiconductor device includes a substrate having an insulating surface, a pixel portion provided over the substrate, and at least some of driver circuits for driving the pixel portion. A transistor included in the pixel portion and a transistor included in the driver circuit are top-gate bottom-contact transistors. Electrodes and a semiconductor layer of the transistor in the pixel portion have light-transmitting properties. The resistance of electrodes in the driver circuit is lower than the electrodes included in the transistor in the pixel portion.