Polysilicon Transistor Surface Smoothing via Sacrificial Oxide Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices using polysilicon transistors face challenges in achieving excellent surface quality and reduced surface roughness, which affects the performance and reliability of the transistors.
Innovation Solution
A method for manufacturing transistors with improved surface quality involves forming a preliminary polysilicon layer, depositing a sacrificial silicon oxide layer, doping the sacrificial layer and the polysilicon layer with argon ions, and then using an etchant to remove the sacrificial layer and reduce the surface roughness of the polysilicon layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polysilicon layer is formed by crystallizing amorphous silicon, then the transistor performance is improved, but the surface roughness increases
Solution Approach 1:
A preliminary polysilicon layer is formed first, then a sacrificial layer is deposited on top of it before the surface treatment process. This preliminary structure allows subsequent processing to improve surface quality without compromising the underlying polysilicon layer that provides transistor performance
Solution Approach 2:
A sacrificial layer (silicon oxide) is introduced as an intermediary between the preliminary polysilicon layer and the surface treatment process. This sacrificial layer enables selective etching that removes protrusions from the polysilicon surface while the layer itself protects underlying regions during the process
2Productivity
If argon ion doping is applied to the sacrificial layer and polysilicon layer, then the etch rate is enhanced, but the process complexity increases
Solution Approach 1:
The physical and chemical parameters of the sacrificial layer and polysilicon layer are modified through argon ion doping. This doping changes the etch rate characteristics of these layers, enabling selective removal of the sacrificial layer and protrusions while maintaining control over the polysilicon layer integrity
Solution Approach 2:
The etching process is applied selectively to specific regions - the sacrificial layer and protrusions are removed while the main polysilicon layer is preserved. The argon ion doping provides enhanced etch rates that allow this selective removal to occur efficiently without requiring excessive processing
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 method effectively reduces the surface roughness of the polysilicon layer to less than 50% of its initial roughness, enhancing the surface quality and reliability of the transistors used in display devices.
Implementation Method 1
providing argon (Ar) ions in an upper portion of the sacrificial layer to dope the sacrificial layer and the preliminary polysilicon layer
Implementation Method 2
providing an etchant to an upper portion of the doped sacrificial layer, and removing the sacrificial layer
Implementation Method 3
the preliminary polysilicon layer may be formed in an operation of performing crystallization by providing an excimer laser to an amorphous silicon layer
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for manufacturing a transistor includes providing a preliminary polysilicon layer including an upper surface on which protrusions are formed, providing a sacrificial layer on the upper surface of the preliminary polysilicon layer, providing argon (Ar) ions in an upper portion of the sacrificial layer to dope the sacrificial layer and the preliminary polysilicon layer, providing an etchant to an upper portion of the doped sacrificial layer, and removing the sacrificial layer, and etching the protrusions to form a polysilicon layer.