Stacked Capacitor Structure for High Aperture Ratio in Semiconductor Devices
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Solution Overview
Problem
In liquid crystal display devices, increasing the capacitance of capacitors to prolong the alignment of liquid crystal molecules under an electric field while maintaining a high aperture ratio and reducing display defects and bezel size is challenging, as larger light-blocking conductive films degrade image quality and increase power consumption.
Innovation Solution
A semiconductor device with a transistor structure that includes a light-transmitting conductive film connected to the gate and source/drain electrodes, overlapping with a gate insulating film, and a nitride insulating film, allowing for a larger capacitor area without reducing the aperture ratio, achieved by using In, Ga, or Zn-based oxide semiconductor films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the area of light-blocking conductive film is increased to increase capacitor area, then capacitance is improved, but aperture ratio is lowered and display quality is degraded
Solution Approach 1:
The patent applies dimensionality change by transitioning from a planar capacitor structure to a three-dimensional stacked structure. The first capacitor is formed with electrodes in a first plane, while the second capacitor is formed with electrodes in a second plane that overlaps the first plane vertically. This stacked configuration increases total capacitance without expanding the lateral footprint, thereby maintaining the aperture ratio while achieving the required charge capacity for prolonged liquid crystal alignment.
Solution Approach 2:
The patent implements nesting by placing the second capacitor structure within the same lateral footprint as the first capacitor. The electrodes of the second capacitor are positioned to overlap with the electrodes of the first capacitor in the vertical direction, effectively nesting one capacitor structure within another. This nested arrangement maximizes the use of available space, increasing total capacitance without occupying additional lateral area that would reduce the aperture ratio.
2Quantity of substance
If the area of light-blocking conductive film is increased to increase capacitor area, then capacitance is improved, but power consumption is increased
Solution Approach 1:
By stacking capacitors in the vertical dimension rather than expanding laterally, the patent achieves increased capacitance without increasing the area of light-blocking conductive films. This maintains efficient light transmission from the backlight, reducing the energy required to illuminate the display and thereby lowering overall power consumption while still providing sufficient charge capacity.
3Quantity of substance
If the area of light-blocking conductive film is increased to increase capacitor area, then capacitance is improved, but bezel size is increased
Solution Approach 1:
The stacked capacitor structure allows increased capacitance to be achieved within the same lateral footprint, preventing any increase in bezel size. The vertical stacking of capacitors ensures that the overall device dimensions remain compact while providing sufficient charge capacity for high-resolution displays with prolonged image holding.
4Manufacturing precision
If oxide semiconductor films are used to form transistors, then manufacturing precision and reliability are improved, but device complexity is increased
Solution Approach 1:
The patent applies multi-functionality by designing the stacked capacitor structure where the same vertical stacking approach serves multiple purposes: it increases capacitance, maintains aperture ratio, reduces power consumption, and prevents bezel enlargement. Additionally, the oxide semiconductor transistors provide normally-off characteristics that work synergistically with the capacitor structure to achieve low power consumption and high reliability without requiring separate control mechanisms.
Data Source
AI summary
To provide a semiconductor device having a high aperture ratio and including a capacitor with a high charge capacitance. To provide a semiconductor device with a narrow bezel. A transistor over a substrate; a first conductive film over a surface over which a gate electrode of the transistor is provided; a second conductive film over a surface over which a pair of electrodes of the transistor is provided; and a first light-transmitting conductive film electrically connected to the first conductive film and the second conductive film are included. The second conductive film overlaps the first conductive film with a gate insulating film of the transistor laid between the second conductive film and the first conductive film.