Trench-Structured Oxide TFT Channel for Mobility and Wafer Uniformity
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Solution Overview
Problem
Conventional thin film transistors face limitations in adjusting the thickness and length of the channel layer and suffer from non-uniform performance across the wafer due to dry etching processes, particularly when using silicon substrates.
Innovation Solution
The method involves depositing and finely patterning oxide semiconductor layers to form trench structures without dry etching, allowing for adjustable thickness and length of the channel layer, enhancing field-effect mobility and uniformity across the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dry etching is used to form trench structures, then field-effect mobility is improved, but uniformity of performance across the wafer is degraded
Solution Approach 1:
The patent replaces the mechanical dry etching process with a deposition-based trench formation method. Instead of removing material through etching, the invention uses selective deposition of oxide semiconductor layers to create trench structures, thereby eliminating the uniformity issues associated with dry etching while maintaining the mobility benefits of trench structures.
Solution Approach 2:
The patent changes the fundamental process parameter from etching (removal) to deposition (addition). By controlling deposition conditions and layer thicknesses, the trench structure is formed through material accumulation rather than removal, enabling better uniformity control across the wafer while achieving the desired field-effect mobility enhancement.
2Ease of manufacture
If conventional planar structure is used, then manufacturing is simpler, but field-effect mobility is limited
Solution Approach 1:
The patent segments the oxide semiconductor layer into multiple layers with different thicknesses (first oxide semiconductor layer and second oxide semiconductor layer). This segmentation creates the trench structure that enhances field-effect mobility while maintaining a relatively simple manufacturing process that builds upon conventional multi-layer deposition techniques.
Solution Approach 2:
The patent transitions from a two-dimensional planar structure to a three-dimensional trench structure by varying the thickness of oxide semiconductor layers in the vertical dimension. This dimensional change enables enhanced field-effect mobility through the trench configuration while extending the conventional planar deposition process into the thickness dimension.
3Length of moving object
If trench structure is formed by dry etching, then channel layer length is reduced, but thickness adjustment is not possible and silicon substrate is required
Solution Approach 1:
The patent changes the deposition parameters (thickness, deposition rate, number of layers) to achieve trench structure formation without dry etching. This enables independent adjustment of channel layer thickness and length, and removes the constraint of requiring silicon substrates, allowing the process to be applied to various substrate types including flexible substrates.
Solution Approach 2:
The patent replaces the dry etching mechanism with a deposition mechanism that uses differences in deposition rate between vertical and horizontal surfaces to form trenches. This substitution eliminates the need for silicon substrates and enables flexible adjustment of channel layer dimensions through control of deposition parameters rather than etching parameters.
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 achieves high field-effect mobility and improved uniformity of performance among thin film transistor dies by forming trench-structured oxide semiconductor layers with thin and thick segments.
Implementation Method 1
depositing and finely patterning oxide semiconductor layers to form trench structures
Data Source
AI summary
A thin film transistor with trench-structured oxide semiconductor layers includes the substrate, the source electrode, the drain electrode, a first oxide semiconductor layer, a second oxide semiconductor layer, the gate insulating layer, and the gate electrode, and a method of manufacturing the same. The method of manufacturing the thin film transistor with trench-structured oxide semiconductor layers composed of thin and thick segments includes arranging the source electrode and the drain depositing first oxide electrode on the substrate, a semiconductor layer on the source electrode and the drain electrode, depositing a second oxide semiconductor layer on the first oxide semiconductor layer, forming the gate insulator layer on the second oxide semiconductor layer, and forming the gate electrode on the gate insulator layer. The trench structure is formed by the first oxide semiconductor layer and the second oxide semiconductor layer to have high field-effect mobility.