Thin Film Transistor Source Drain Electrode Etching
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Solution Overview
Problem
The manufacturing process of compound semiconductor thin film transistors is hindered by the vulnerability of the active layer to etching solutions during the formation of source and drain electrodes, leading to device performance issues and increased complexity and cost due to the need for an etch barrier layer in the BCE process.
Innovation Solution
The use of source and drain electrodes formed from at least two materials that create a cell reaction in an etching solution, allowing for simultaneous etching without damaging the active layer, thereby eliminating the need for an etch barrier layer and reducing the number of patterning processes and manufacturing cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the BCE process is used to manufacture compound semiconductor TFTs, then the manufacturing process can be simplified with fewer masks and process steps, but the active layer will be damaged by the etching solution
Solution Approach 1:
An etch barrier layer is introduced as an intermediary between the active layer and the etching solution. This layer protects the active layer from chemical damage while allowing the BCE process to proceed. The etch barrier layer is selectively removed later to enable source and drain electrode formation, thus resolving the contradiction between process simplicity and active layer protection.
Solution Approach 2:
The source and drain electrodes are formed using composite materials (e.g., Al/ITO or Al/In2O3) that enable selective etching. The etching solution reacts with specific materials in the composite structure while leaving the active layer intact, allowing the BCE process to simplify manufacturing without compromising active layer integrity.
2Reliability
If an etch barrier layer is added to protect the active layer, then the active layer damage is prevented, but the mask number increases and the process becomes more complicated
Solution Approach 1:
The etch barrier layer formation is merged with the existing gate electrode formation process. Both structures are created simultaneously in the same deposition step, reducing the total number of separate manufacturing steps and minimizing the increase in process complexity while still providing active layer protection.
Solution Approach 2:
The etch barrier layer serves multiple functions: it protects the active layer during etching, acts as a diffusion barrier, and can be integrated with the gate electrode structure. This multi-functionality reduces the need for additional separate protective layers, thereby limiting the increase in manufacturing complexity.
3Reliability
If an etch barrier layer is added to protect the active layer, then the active layer damage is prevented, but the manufacturing cost increases
Solution Approach 1:
The etch barrier layer is deposited together with the gate electrode material in a single deposition process. This merging of steps eliminates the need for separate deposition equipment and process time, thereby minimizing the additional manufacturing cost despite adding a protective layer.
Solution Approach 2:
The etch barrier layer is designed to be temporarily present and then selectively removed after serving its protective function. This allows the layer to provide necessary protection during critical process steps while not requiring permanent retention, reducing material cost and simplifying subsequent 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
This approach enables the direct use of the back channel etch process for compound semiconductor thin film transistors, reducing the risk of active layer damage, simplifying the manufacturing process, and lowering costs while maintaining high etching efficiency.
Implementation Method 1
the at least two materials being able to create a cell reaction in a corresponding etching solution so as to be etched
Data Source
AI summary
A thin film transistor, a manufacturing method thereof, and a display device are provided. The thin film transistor includes a gate electrode (21), an active layer (23), a source electrode (241) and a drain electrode (242). The source electrode (241) and the drain electrode (242) are formed of at least two materials, the forming materials of the source electrode (241) and the drain electrode (242) can create a cell reaction in a corresponding etching solution so as to be etched, and material of the active layer (23) is not corroded by the etching solution. With the thin film transistor and manufacturing method thereof according to embodiments of the invention, a problem that an active layer is liable to be corroded in an etching procedure of a source electrode and a drain electrode can be solved, and thus the thin film transistor device can be manufactured by using a back channel etch process. Consequently, the process number for manufacture of the thin film transistor is decreased, and the manufacturing cost is saved.