Active Switch With Segmented Amorphous Silicon Layers
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Solution Overview
Problem
The Gate Driver on Array (GOA) technology in display panels experiences defects due to leakage current in Thin Film Transistors (TFTs), leading to reduced display brightness and threshold voltage shifts, affecting the display quality and reliability.
Innovation Solution
A manufacturing method for an active switch is developed, involving a semiconductor composite layer with multiple doped amorphous silicon layers and a channel region treated in a preset gas atmosphere, which increases the energy barrier and reduces leakage current, enhancing illumination stability and threshold voltage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional TFT structure with single-layer doped semiconductor is used, then the manufacturing process is simple, but leakage current is high and threshold voltage shifts occur
Solution Approach 1:
The semiconductor layer is segmented into multiple sub-layers with different doping concentrations (first N-type heavily doped, first N-type lightly doped, second N-type heavily doped, second N-type lightly doped). This segmentation creates a multi-layered structure where each layer serves specific functions: heavily doped layers provide good contact and reduce leakage, while lightly doped layers control threshold voltage and reduce hydrogen-induced shifts, thereby resolving the contradiction between reliability and structural complexity.
Solution Approach 2:
Different regions of the semiconductor layer are assigned different doping concentrations to achieve local optimization. The heavily doped regions (N++) provide low resistance contacts and reduce leakage current, while the lightly doped regions (N-) control the threshold voltage and minimize hydrogen-induced threshold voltage shifts. This local quality differentiation allows the device to simultaneously achieve low leakage and stable threshold voltage despite the increased structural complexity.
2Reliability
If hydrogen doping is used to improve semiconductor properties, then electrical characteristics improve, but threshold voltage shifts due to hydrogen trapping occur
Solution Approach 1:
The invention changes the doping concentration parameter across different layers, creating a gradient structure with both heavily doped (N++) and lightly doped (N-) regions. This parameter variation allows the lightly doped layers to act as buffer zones that reduce hydrogen trapping effects, thereby stabilizing the threshold voltage while maintaining good electrical characteristics through the heavily doped contact layers.
3Ease of manufacture
If GOA driving mode is used to integrate gate driver on array substrate, then product cost is reduced, but display quality deteriorates due to leakage current
Solution Approach 1:
The segmented multi-layer semiconductor structure with varying doping concentrations reduces leakage current in each layer, thereby improving overall display brightness and quality while maintaining the cost-effective GOA integration approach. The heavily doped layers ensure low resistance for signal transmission, while lightly doped layers minimize leakage, resolving the contradiction between manufacturing ease and display quality.
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 leakage current and improves display quality by increasing the energy barrier and repairing channel region damage, resulting in enhanced illumination stability and reduced threshold voltage drift.
Implementation Method 1
by arranging the semiconductor composite layer (the first N-type heavily doped amorphous silicon layer, the first N-type lightly doped amorphous silicon layer, the second N-type heavily doped amorphous silicon layer and the second N-type lightly doped amorphous silicon layer) with a plurality of concentration gradients to replace the original single-layer doped layer, energy barrier between the source and drain electrodes and the semiconductor composite layer can be increased, potential barrier of hole transmission can be improved, and the leakage current of a back channel in a switch device can be reduced
Implementation Method 2
by placing the channel region in a preset gas atmosphere for heating treatment, the damage of the channel region can be repaired, weak bonds in the amorphous silicon can be reduced
Data Source
AI summary
The present application relates to an active switch, a manufacturing method thereof and a display device. The manufacturing method of the active switch includes: sequentially forming a gate electrode, a gate insulating layer, an active layer, a semiconductor composite layer and a source electrode and a drain electrode on a substrate. The semiconductor composite layer includes a first N-type heavily doped amorphous silicon layer, a first N-type lightly doped amorphous silicon layer, a second N-type heavily doped amorphous silicon layer and a second N-type lightly doped amorphous silicon layer which are sequentially stacked, where the ion doping concentration of the first N-type heavily doped amorphous silicon layer is lower than that of the second N-type heavily doped amorphous silicon layer, and the ion doping concentration of the first N-type lightly doped amorphous silicon layer is higher than that of the second N-type lightly doped amorphous silicon layer.