Polysilicon TFT Active Layer with Metal Catalysts for Higher Mobility
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Solution Overview
Problem
Existing semiconductor devices have low mobility due to small grain size of polysilicon caused by process limitations, which fails to meet the demands for narrow bezel, high aperture ratio, high brightness, and high resolution in display technology.
Innovation Solution
A semiconductor device with a thin film transistor structure that includes a substrate, a buffer layer, and an active layer, where a metal layer with metal blocks is in direct contact with the active layer, acting as a catalyst to increase the size of crystal grains in polysilicon, reducing grain boundaries and improving mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polysilicon is formed after laser annealing in the manufacturing process, then carrier mobility is improved and on-state current is increased, but the grain size of polysilicon becomes small due to process limitations, resulting in low carrier mobility
Solution Approach 1:
The patent applies preliminary action by forming metal blocks (catalysts) in the buffer layer before forming the polysilicon active layer. These metal blocks are prepared in advance to catalyze the formation of large-grained polysilicon during laser annealing, thereby resolving the contradiction between achieving high on-state current and maintaining large grain size that would otherwise be limited by conventional processes
Solution Approach 2:
The patent uses metal blocks as intermediary catalysts between the laser annealing process and the polysilicon formation. These metal blocks (such as aluminum, nickel, gallium, or indium) mediate the transformation of amorphous silicon into large-grained polysilicon with high carrier mobility, enabling the system to overcome the inherent process limitations that would otherwise produce small grain sizes
2Ease of manufacture
If the grain size of polysilicon is small, then the manufacturing process is simpler, but carrier mobility is low and on-state current is insufficient
Solution Approach 1:
The metal blocks serve as intermediary catalysts that enable the formation of large-grained polysilicon without significantly complicating the manufacturing process. The metal blocks are formed using standard photolithography and sputtering techniques, and their catalytic effect during laser annealing naturally produces large grains, thereby maintaining ease of manufacture while dramatically improving carrier mobility
Solution Approach 2:
The patent changes the physical and chemical parameters of the buffer layer by incorporating metal blocks with specific melting points (less than 1410°C) and catalytic properties. This parameter change in the buffer layer composition enables the laser annealing process to produce large-grained polysilicon with high carrier mobility, resolving the contradiction between manufacturing simplicity and device performance
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 effectively increases the size of crystal grains in polysilicon, reducing grain boundaries and enhancing the mobility of semiconductor devices, thereby addressing the limitations of existing technologies in achieving high resolution and brightness.
Implementation Method 1
when the active layer is converted from amorphous silicon to polysilicon, due to a catalytic effect of the metal block, a size of the crystal grains in the polysilicon becomes larger
Data Source
AI summary
The present application provides a semiconductor device and an electronic device. In the semiconductor device, a metal layer is provided on the side of the active layer facing the buffer layer, and the metal layer includes at least one metal block, so that the metal block is in direct contact with at least part of the active layer, then when the active layer is converted from amorphous silicon to polycrystalline silicon, due to the catalytic effect of the metal block, the size of the crystal grains in the polycrystalline silicon becomes larger, which reduces the crystal grain boundaries in the polycrystalline silicon and improves the mobility of the semiconductor device.