Thin Film Transistor Substrate With Shared Gate Electrode Capacitor
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Solution Overview
Problem
The decreasing pixel area in display devices makes it difficult to arrange a TFT and a capacitor with sufficient storage capacitance, limiting the resolution and performance of display devices.
Innovation Solution
A thin film transistor substrate design where the capacitor includes a pair of electrodes with one electrode serving as the gate electrode of the TFT, allowing for increased storage capacitance by overlapping the TFT and capacitor areas, enabling efficient storage of data voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel area is decreased to increase resolution, then display resolution is improved, but the area available for arranging TFT and capacitor is reduced
Solution Approach 1:
The gate electrode of the TFT is merged with one electrode of the capacitor, forming a shared conductive structure. This integration allows the capacitor to be formed within the TFT structure area, effectively reducing the total pixel area required while maintaining sufficient storage capacitance for high-resolution displays
Solution Approach 2:
The capacitor electrodes are arranged in a stacked configuration above and below the gate electrode along the vertical dimension, rather than requiring lateral separation in the planar area. This vertical stacking enables the capacitor to occupy three-dimensional space within the pixel, increasing storage capacitance without increasing pixel footprint
2Reliability
If capacitor area is increased to ensure sufficient storage capacitance, then storage capacitance is improved, but the area available for TFT arrangement is reduced
Solution Approach 1:
The gate electrode serves dual functions as both the gate electrode for the TFT and one electrode (either upper or lower) of the capacitor. This merging eliminates the need for separate capacitor electrode structures, maximizing the use of available area while ensuring sufficient storage capacitance
Solution Approach 2:
The gate electrode is designed to perform multiple functions: controlling the TFT channel and serving as an electrode for charge storage in the capacitor. This multi-functionality increases the effective storage capacitance within the same physical area that would otherwise be occupied by separate TFT and capacitor structures
Data Source
AI summary
A thin film transistor substrate including a thin film transistor and a capacitor formed of a pair of electrodes, which includes: a first electrode above a substrate; a first insulating film above the first electrode; a second electrode above the first insulating film; a second insulating film above the second electrode; and a semiconductor layer above the second insulating film, in which the capacitor includes the first electrode as one of the pair of electrodes and the second electrode as the other of the pair of electrodes, and the thin film transistor includes the second electrode as a gate electrode, the second insulating film as a gate insulating film, and the semiconductor layer as a channel layer.