OLED Transistor LDD Formation via Selective Epitaxy
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Solution Overview
Problem
The manufacturing process for organic light emitting diode (OLED) displays is complex and costly due to the requirement of a separate mask and high-temperature activation processes for forming lightly doped drain (LDD) regions in transistors, limiting material selection and increasing production costs.
Innovation Solution
A method for forming lightly doped regions in transistors without using a separate mask, employing a selective epitaxial growth process to create layers with different impurity doping concentrations, which simplifies the process and reduces costs by allowing a low-temperature approach, enabling the use of low-heat resistant materials and low-priced glass substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate mask and high-temperature activation process are used to form lightly doped drain (LDD) regions, then transistor reliability is improved by minimizing leakage current, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the LDD formation and source/drain electrode formation into a single integrated process. The source/drain electrodes are formed to directly overlap the LDD regions, eliminating the need for separate masks and processes. This merging of steps reduces manufacturing complexity while maintaining the transistor reliability benefits of LDD structures.
Solution Approach 2:
The source/drain electrodes serve multiple functions: they act as both the electrical contacts and as the masking structure for LDD formation. This multi-functional design eliminates the need for dedicated LDD masks, reducing process steps and complexity while achieving the same reliability improvement through leakage current minimization.
2Manufacturing precision
If high-temperature activation process is used for LDD formation, then doping activation is improved, but manufacturing cost increases and material selection is limited
Solution Approach 1:
The patent changes the temperature parameter from high-temperature activation to low-temperature formation processes. The source/drain electrodes and LDD regions are formed at lower temperatures through the integrated process, reducing manufacturing costs and enabling the use of low-heat resistant organic materials that would be damaged by high-temperature processing.
Solution Approach 2:
The patent replaces the thermal activation mechanism with an electrochemical or vapor-phase deposition process that occurs at lower temperatures. Instead of using high-temperature heat treatment to activate doping, the process uses controlled deposition methods to form the doped structures, thereby reducing energy consumption and material constraints.
3Manufacturing precision
If high-temperature activation process is used, then doping efficiency is improved, but the range of material selection is narrowed
Solution Approach 1:
The patent changes the temperature parameter from high to low, enabling the use of organic materials and low-heat resistant substances that would decompose or degrade at high temperatures. The low-temperature integrated process maintains sufficient doping efficiency through alternative mechanisms while expanding material compatibility to include flexible substrates and organic semiconductors.
Solution Approach 2:
The patent employs composite material systems where the source/drain electrodes and semiconductor layers are formed as integrated composite structures. This allows the use of organic materials, polymers, and low-heat resistant compounds that combine electrical functionality with thermal stability at lower processing temperatures, thereby expanding the range of usable materials.
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
This approach simplifies the manufacturing process, reduces production costs, enhances transistor contact characteristics, and broadens the selection of materials, including low-heat resistant organic materials, while eliminating the need for high-temperature activation processes.
Implementation Method 1
employing a selective epitaxial growth process to create layers with different impurity doping concentrations
Data Source
AI summary
An organic light emitting diode display having a lightly doped region formed in a transistor for simplifying manufacturing process and reducing manufacturing costs is provided. The organic light emitting diode display includes: a substrate, a transistor on the substrate, and an organic light emitting diode (OLED) connected to the transistor, wherein the transistor includes a semiconductor member on the substrate, an insulating member on the semiconductor member, a source member and a drain member disposed on the semiconductor member and respectively disposed at opposite sides of the insulating member, and a gate electrode on the insulating member, wherein each of the source member and the drain member includes a plurality of layers having different impurity doping concentrations.