Organic Light Emitting Display Polycrystalline Silicon Crystallization
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Solution Overview
Problem
Existing organic light emitting displays face challenges in achieving optimal performance due to limitations in crystallization methods for polycrystalline silicon layers, which affect the uniformity and size of crystal structures, impacting the efficiency and reliability of thin film transistors.
Innovation Solution
The method involves forming a substrate with a buffer layer containing a metal catalyst, where the first semiconductor layer is crystallized using a metal catalyst and the second semiconductor layer is crystallized by solid phase crystallization, with specific metal catalysts like Ni, Pd, Ag, Au, Al, Sn, Sb, Cu, and Cd, to create polycrystalline silicon layers with varying crystal sizes, optimizing the performance of thin film transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If solid phase crystallization method is used, then uniform crystal size is achieved, but crystal size remains small
Solution Approach 1:
The invention divides the crystallization process into two distinct stages: first, solid phase crystallization creates uniformly sized crystal seeds; second, metal-induced lateral crystallization allows these seeds to grow into large crystals. This segmentation resolves the contradiction by achieving both uniformity (from stage one) and large size (from stage two).
Solution Approach 2:
The solid phase crystallization is performed as a preliminary step to create uniformly distributed crystal seeds before the metal-induced crystallization. This preliminary action ensures that the subsequent growth phase starts with uniform nucleation sites, maintaining crystal size uniformity while enabling large final crystal dimensions.
2Length of moving object
If metal induced crystallization method is used, then large crystal size is achieved, but crystal uniformity decreases
Solution Approach 1:
The invention segments the crystallization process so that metal catalyst is introduced only in the second stage for lateral growth, while the first stage uses solid phase crystallization to establish uniform crystal seeds. This segmentation prevents metal-induced non-uniformity during nucleation while still achieving large crystal sizes during the growth phase.
Solution Approach 2:
The metal catalyst is applied locally and selectively to specific regions where large crystal growth is desired, rather than uniformly throughout the entire semiconductor layer. This local application allows large crystal size in targeted areas while maintaining uniformity in regions where solid phase crystallization dominates.
3Reliability
If polycrystalline silicon layer with large crystal size is formed, then thin film transistor performance improves, but manufacturing complexity increases
Solution Approach 1:
The invention merges two crystallization methods into a single integrated process flow: solid phase crystallization followed by metal-induced lateral crystallization. This combination achieves high-performance large crystal polycrystalline silicon while using standard semiconductor manufacturing techniques, thereby improving transistor performance without excessively increasing manufacturing complexity.
Solution Approach 2:
The metal catalyst serves as an intermediary substance that enables the transition from small uniform crystals to large crystals. By introducing this intermediary element only in the second stage, the process achieves large crystal sizes necessary for high-performance transistors while keeping the overall manufacturing process manageable through controlled, staged implementation.
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 enhances the performance of organic light emitting displays by improving the characteristics of thin film transistors, such as leakage and driving currents, leading to improved device reliability and efficiency.
Implementation Method 1
The metal induced crystallization (MIC) method, the metal induced lateral crystallization (MILC) method, a super grain silicon crystallization (SGS) method, etc., using a metal catalyst, may form a polycrystalline silicon layer having a large crystal size.
Implementation Method 2
portions of the buffer layer corresponding to a source/drain region of the first semiconductor layer include a metal catalyst
Data Source
AI summary
An organic light emitting display and method of fabricating thereof, the display including a substrate including a first thin film transistor region and a second thin film transistor region; a buffer layer on the substrate; a first and a second semiconductor layer on the buffer layer; a gate insulating layer on the substrate; gate electrodes on the gate insulating layer and corresponding to the first semiconductor layer and the second semiconductor layer, respectively; source/drain electrodes insulated from the gate electrode and being connected to the first semiconductor layer and the second semiconductor layer, respectively; an insulating layer on the substrate; a first electrode connected to the source/drain electrode electrically connected to the first semiconductor layer; an organic layer on the first electrode; and a second electrode on the organic layer, wherein portions of the buffer layer corresponding to a source/drain region of the first semiconductor layer include a metal catalyst.