Thin-Film Transistor Electrode Layout for Lower Off-Current
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Solution Overview
Problem
Existing thin-film transistor substrates for display apparatuses face challenges in enhancing off-current characteristics without increasing the number of mask processes, which can lead to increased leakage current and deterioration in performance.
Innovation Solution
A thin-film transistor substrate is designed with a semiconductor layer that includes a first conductive region, a second conductive region, and a first semiconductor region between them. The substrate features a lower electrode and an upper electrode that overlap the semiconductor region, with the first width of the semiconductor region being greater than the second width of the lower electrode, and the boundaries between the semiconductor region and the conductive regions coinciding with the edges of the electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional thin-film transistor structure is used, then the manufacturing process is simple, but the off-current characteristics deteriorate due to strong electric field effects
Solution Approach 1:
The patent segments the electrode structure into two separate electrodes: a first electrode positioned at a first position relative to the semiconductor layer, and a second electrode positioned at a second position. This segmentation allows independent optimization of each electrode's position and dimensions, enabling reduced electric field strength at critical interfaces while maintaining manufacturing feasibility through standardized layer-by-layer deposition processes
Solution Approach 2:
The patent extends the solution into the vertical dimension by positioning electrodes at different heights relative to the semiconductor layer. The first electrode is at a first position and the second electrode is at a second position, creating a three-dimensional electrode configuration. This dimensional approach reduces the strength of the electric field at the semiconductor-electrode interface without requiring changes to the planar semiconductor layer structure, thus maintaining manufacturing simplicity while improving off-current characteristics
2Object-generated harmful factors
If the electric field strength is reduced to improve off-current characteristics, then leakage current decreases, but the device dimensions must be adjusted
Solution Approach 1:
The patent applies local quality by creating non-uniform electric field distribution through strategically positioned electrodes. The first electrode at the first position and the second electrode at the second position generate a localized electric field configuration that reduces field strength specifically at the semiconductor-electrode interface where it causes harmful effects, while maintaining sufficient field strength in the channel region for proper transistor operation. This localized approach reduces leakage current without requiring overall device dimension changes
Data Source
AI summary
Provided are a thin-film transistor substrate that has enhanced electrical characteristics, such as off-current characteristics of a thin-film transistor, without increasing the number of mask processes, a display apparatus, and a method of manufacturing the thin-film transistor substrate. The thin-film transistor substrate includes: a semiconductor layer including a first conductive region, a second conductive region, and a first semiconductor region; a lower electrode disposed on the semiconductor layer and at least partially overlapping the first semiconductor region; and an upper electrode disposed on the lower electrode and at least partially overlapping the first semiconductor region, a first boundary between the first semiconductor region and the first conductive region coincides with an edge of the upper electrode, and a second boundary between the first semiconductor region and the second conductive region coincides with an edge of the lower electrode or an edge of the upper electrode.