Semiconductor Device with Light-Transmitting Capacitor Electrode
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Solution Overview
Problem
Existing semiconductor devices with oxide semiconductors face challenges in achieving high aperture ratio, low power consumption, and reliable electrical characteristics due to limitations in capacitor charge capacity and transistor off-state current, particularly when using oxide semiconductor films for electrodes.
Innovation Solution
A semiconductor device design incorporating a gate insulating film, an oxide semiconductor film, a light-transmitting conductive film with higher hydrogen concentration, and a nitride insulating film to increase capacitor charge capacity while maintaining a high aperture ratio, utilizing a microcrystalline region with indium or zinc, and optimizing the hydrogen concentration and resistivity of the conductive films to reduce off-state current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If one electrode of the capacitor is formed using a semiconductor film, then the aperture ratio can be increased, but the capacitance value charged in the capacitor becomes lower than a predetermined value
Solution Approach 1:
The patent applies parameter changes by controlling the hydrogen concentration in the oxide semiconductor film to be 1×10^19 atoms/cm³ or less, and optimizing the film thickness to 50 nm or less. These parameter adjustments enable the semiconductor film to achieve both high transparency (maintaining aperture ratio) and sufficient charge capacity (achieving predetermined capacitance value) by precisely controlling its electrical and optical properties.
Solution Approach 2:
The patent uses composite material structure by forming a layered configuration with the oxide semiconductor film as one electrode of the capacitor, combined with a light-transmitting conductive film and dielectric film. This composite structure allows the device to simultaneously achieve high aperture ratio and sufficient capacitance by leveraging the complementary properties of different materials.
2Quantity of substance
If the area of a light-blocking conductive film is increased to increase the area of a portion where a pair of electrodes overlaps with each other, then the charge capacity of the capacitor can be increased, but the aperture ratio of a pixel is lowered
Solution Approach 1:
The patent inverts the conventional approach by making the semiconductor film itself transparent rather than using opaque conductive materials for the capacitor electrode. This inversion allows light to pass through the electrode, maintaining high aperture ratio while the semiconductor film's unique properties enable it to store sufficient charge capacity, thus resolving the traditional trade-off between these two parameters.
Solution Approach 2:
By changing the optical parameter (transparency) of the electrode material from opaque to transparent through selecting and optimizing the oxide semiconductor film with controlled hydrogen concentration and thickness, the patent achieves both high aperture ratio and sufficient charge capacity without requiring large areas of light-blocking conductive film.
3Loss of energy
If the off-state current of the transistor is not sufficiently reduced, then power consumption increases, but achieving low off-state current requires precise control of hydrogen concentration and film properties
Solution Approach 1:
The patent applies parameter changes by establishing specific thresholds for hydrogen concentration (1×10^19 atoms/cm³ or less) and film thickness (50 nm or less) in the oxide semiconductor film. By controlling these parameters within defined ranges, the invention achieves sufficiently low off-state current to reduce power consumption while providing clear manufacturing specifications that balance precision requirements with fabrication feasibility.
Data Source
AI summary
A semiconductor device includes a transistor including an insulating film, an oxide semiconductor film, a gate electrode overlapping with the oxide semiconductor film, and a pair of electrodes in contact with the oxide semiconductor film; a capacitor including a first light-transmitting conductive film over the insulating film, a dielectric film over the first light-transmitting conductive film, and a second light-transmitting conductive film over the dielectric film; an oxide insulating film over the pair of electrodes of the transistor; and a nitride insulating film over the oxide insulating film. The dielectric film is the nitride insulating film, the oxide insulating film has a first opening over one of the pair of electrodes, the nitride insulating film has a second opening over the one of the pair of electrodes, and the second opening is on an inner side than the first opening.