Unified Etch Stopping Layer and Electrodes in Light Sensing Transistors
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Solution Overview
Problem
Liquid crystal displays require dual sensors for touch and image sensing, leading to different semiconductor materials and processes, which can result in defects and leakage current due to the etch stopping layer's thickness affecting thin film etching, thereby deteriorating electrical properties.
Innovation Solution
A display panel design where the etch stopping layer, source electrode, and drain electrode are made of the same material, and a method for manufacturing light sensing transistors with a light blocking layer and insulating layer to prevent defective patterns and reduce leakage current, allowing for improved electrical properties and reduced process complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an etch stopping layer is employed to separate processes for preparing semiconductors in infrared and visible sensing transistors, then process separation is achieved, but etching of thin films formed on the etch stopping layer may not properly occur, causing defects in etched patterns
Solution Approach 1:
The patent removes the etch stopping layer from the structure entirely. Instead of using a separate etch stopping layer, the invention uses the source electrode and drain electrode as the etch stopping function, thereby eliminating the layer that causes etching defects while maintaining process separation capability.
Solution Approach 2:
The patent combines the etch stopping layer and source/drain electrodes into a single integrated structure made of the same material. This merging eliminates the need for a separate etch stopping layer while maintaining both the etch stopping function and the electrode function, thereby preventing etching defects.
2Ease of manufacture
If an etch stopping layer is used to separate semiconductor preparation processes, then process separation is enabled, but leakage current is generated in the transistors and etch stopping layer, deteriorating electrical properties
Solution Approach 1:
The patent merges the etch stopping layer and source/drain electrodes into a single structure made of the same material. This integration eliminates the separate etch stopping layer that generates leakage current, thereby improving electrical properties while maintaining process separation through the manufacturing sequence.
Solution Approach 2:
The patent extracts and removes the problematic etch stopping layer from the transistor structure, replacing its function with the source/drain electrode structure itself, thereby eliminating the source of leakage current.
3Ease of manufacture
If the thickness of the etch stopping layer is increased to improve process separation, then process control is enhanced, but etching of thin films on the etch stopping layer fails, causing defective patterns
Solution Approach 1:
The patent removes the etch stopping layer entirely and replaces its function with the source/drain electrode structure. This eliminates the thickness-related etching problems while maintaining process control through the sequential manufacturing steps.
Data Source
AI summary
A display device includes an infrared sensing transistor and a visible sensing transistor. The visible sensing transistor includes a semiconductor on a substrate; an ohmic contact on the semiconductor; an etch stopping layer on the ohmic contact; a source electrode and a drain electrode on the etch stopping layer; a passivation layer on the source electrode and the drain electrode; and a gate electrode on the passivation layer. The etch stopping layer may be composed of the same material as the source electrode and the drain electrode. The infrared sensing transistor is similar to the visible sensing transistor except the etch stopping layer is absent.