Display Panel Three-Electrode Capacitor with Thin High-K Dielectric
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Solution Overview
Problem
Current OLED display panels face challenges with low capacitance values in storage capacitors, which affect charge-discharge and charge retention capabilities, and require multiple gate masks, leading to a thick film that does not meet ultra-thin display technology requirements.
Innovation Solution
A display panel design with a three-layered sandwich storage capacitor structure, utilizing a thin Al2O3 dielectric layer and integrating the formation of components like the second capacitor electrode with other transistors' layers, reducing the number of masks needed and enhancing capacitance through a higher dielectric constant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a thick insulating layer (2000-10000 angstroms) is used on the second capacitor electrode, then the LTPO substrate has greater thickness, but this cannot meet ultra-thin display technology requirements
Solution Approach 1:
The patent changes the dielectric constant parameter by replacing traditional SiOx/SiNx materials with high-k dielectric materials such as Al2O3, HfO2, or TiO2. This material substitution allows the capacitor to achieve the same capacitance value with a much thinner dielectric layer (500-2000 angstroms instead of 2000-10000 angstroms), thereby reducing substrate thickness while maintaining charge retention capability
Solution Approach 2:
The patent introduces a third capacitor electrode below the first capacitor electrode, creating a stacked capacitor structure with three electrodes. This dimensional change from a planar two-electrode capacitor to a vertical three-electrode capacitor increases the effective capacitance area without increasing the lateral footprint, allowing for thinner overall structure while maintaining or enhancing charge retention
2Reliability
If traditional capacitor dielectric materials (SiOx or SiNx) with small dielectric constant are used, then capacitance value is relatively small, but this cannot meet the requirements for charge-discharge and charge retention capabilities
Solution Approach 1:
The patent fundamentally changes the dielectric constant parameter by adopting high-k dielectric materials (Al2O3, HfO2, TiO2) with dielectric constants significantly higher than traditional SiOx/SiNx materials. This parameter change enables the capacitor to achieve high capacitance values with thin dielectric layers, simultaneously satisfying both the capacitance requirement and the ultra-thin display requirement
Solution Approach 2:
The patent employs composite material structures combining multiple dielectric layers with different properties. The capacitor dielectric layer is formed as a composite of high-k dielectric materials, potentially combined with other functional layers, to achieve optimal balance between capacitance value, thickness, and electrical performance
3Ease of manufacture
If three gate masks are used for formation of gate of LTPS TFT, second capacitor electrode, and gate of IGZO TFT, then manufacturing process is complicated
Solution Approach 1:
The patent merges the formation of the second capacitor electrode with the formation of the IGZO TFT gate into a single process step using one gate mask. The second capacitor electrode and IGZO gate are formed simultaneously in the same layer, eliminating the need for separate masking steps and reducing manufacturing complexity
Solution Approach 2:
The gate mask serves multiple functions simultaneously: it defines both the second capacitor electrode and the IGZO TFT gate in a single application. This multi-functionality reduces the total number of masks required and simplifies the manufacturing process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution increases capacitance values to meet charge-discharge and retention needs while reducing panel thickness, aligning with ultra-thin display technology standards.
Implementation Method 1
utilizing a thin Al2O3 dielectric layer and integrating the formation of components like the second capacitor electrode with other transistors' layers, reducing the number of masks needed and enhancing capacitance through a higher dielectric constant
Data Source
AI summary
The present application relates to a display panel and a manufacturing method thereof. The display panel of the present application includes a storage capacitor. The storage capacitor includes: a first capacitor electrode, a first capacitor dielectric, a second capacitor electrode, a second capacitor dielectric, an interlayer insulating layer, and a third capacitor electrode. Since the second capacitor dielectric is relatively thin, and a dielectric constant of the second capacitor dielectric is relatively high, a capacitance value of the entire storage capacitor can be increased to meet the requirements of the display panel for charge-discharge and charge retention capabilities.