Thin Film Transistor Laser Crystallization and Dopant Diffusion
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Solution Overview
Problem
Current methods for manufacturing thin film transistors in flat panel displays, such as OLEDs, face challenges in achieving uniform doping and crystallization of the active layer, which affect the electrical properties and efficiency of the transistors.
Innovation Solution
A method involving the formation of an active layer in an amorphous state on a substrate, followed by crystallization using laser irradiation, and subsequent doping of the gate insulating layer to diffuse dopants uniformly into the active layer, including additional doping and activation of contact portions using the gate electrode as a mask, simplifies the doping process and improves electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional doping methods are used to dope the active layer, then the doping process can be completed, but uniform dopant distribution is difficult to achieve and multiple process steps are required
Solution Approach 1:
The gate insulating layer serves as an intermediary carrier containing the dopant. Instead of directly doping the active layer, the dopant is first incorporated into the gate insulating layer, which then acts as a reservoir to uniformly supply dopant to the active layer through controlled diffusion, achieving uniform doping while simplifying the process
Solution Approach 2:
The gate insulating layer formation process is merged with the doping process by incorporating dopant during gate insulating layer deposition. This combines two previously separate steps (forming insulating layer and doping) into one, reducing process complexity while ensuring uniform dopant distribution
2Productivity
If separate crystallization and doping processes are used, then each process can be optimized, but manufacturing time and process complexity increase
Solution Approach 1:
The laser irradiation process simultaneously performs both crystallization of the active layer and diffusion of dopant from the gate insulating layer. This merges two previously separate thermal processes into one, reducing manufacturing time and process complexity while maintaining optimization of each function
Solution Approach 2:
The laser irradiation continuously provides thermal energy that simultaneously drives both crystallization and dopant diffusion processes. By maintaining continuous heating, both transformations occur in sequence within the same process window, improving productivity without sacrificing process optimization
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 method enhances the electrical properties of the thin film transistors by ensuring uniform dopant distribution and simultaneous crystallization and doping, thereby improving the manufacturing efficiency and productivity of thin film transistors.
Implementation Method 1
irradiating laser so that the dopant of the gate insulating layer diffuses into the active layer
Implementation Method 2
the dopant of the gate insulating layer diffuses into the active layer
Implementation Method 3
irradiating the laser may include crystallizing the active layer from the amorphous state into a crystalline state by irradiating the laser
Data Source
AI summary
A method of manufacturing a thin film transistor is disclosed. In one aspect, the method includes forming an active layer over a substrate and forming a gate insulating layer containing a dopant over the active layer. The method also includes irradiating laser light onto the gate insulating layer such that the dopant of the gate insulating layer diffuses into the active layer.