Photoelectric Sensor Stack With Inorganic Barrier for TFT Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical fingerprint sensors face reliability issues due to impurity contamination of thin-film transistors when photoelectric conversion elements and electrodes are formed on an insulating substrate, leading to reduced performance.
Innovation Solution
A detection device is designed with an insulating substrate, photoelectric conversion elements, a first switching element, and an inorganic insulating layer between the photoelectric conversion element and the switching element, which helps to prevent impurity diffusion and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If photoelectric conversion elements and electrodes are formed on an insulating substrate, then the fingerprint sensor can be manufactured with integrated circuits, but impurities may enter the thin-film transistors causing reduced reliability
Solution Approach 1:
An inorganic insulating layer is introduced as an intermediary barrier between the photoelectric conversion element formation process and the thin-film transistor formation process. This layer prevents impurity diffusion from the photoelectric conversion elements into the thin-film transistors, thereby maintaining transistor reliability while allowing both components to coexist on the same insulating substrate
Solution Approach 2:
The insulating substrate is divided into distinct functional regions: a detection area containing photoelectric conversion elements and a peripheral area containing thin-film transistor circuits. This spatial segmentation, combined with the inorganic insulating layer, isolates the two regions to prevent impurity contamination while enabling integrated manufacturing
2Device complexity
If thin-film transistors are formed on the same substrate as photoelectric conversion elements, then device integration is achieved, but impurity diffusion reduces signal-to-noise ratio
Solution Approach 1:
The inorganic insulating layer serves as a protective barrier that prevents impurity diffusion from the photoelectric conversion element region to the thin-film transistor region. This maintains the electrical integrity and signal quality of the transistors, thereby preserving high signal-to-noise ratio while achieving device integration
Solution Approach 2:
Different regions of the substrate are treated differently: the detection area allows photoelectric conversion element formation while the peripheral area is protected by the inorganic insulating layer during transistor formation. This localized protection strategy maintains measurement precision in the transistor regions while enabling integration
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 effectively reduces impurity diffusion, improving the reliability and signal-to-noise ratio of the detection device by using an inorganic insulating layer to act as a barrier, thereby maintaining the integrity of the thin-film transistors and enhancing the detection performance.
Implementation Method 1
an inorganic insulating layer provided between the photoelectric conversion element and the first switching element in a normal direction of the insulating substrate
Implementation Method 2
a plurality of photoelectric conversion elements that are arranged in a detection area of the insulating substrate, and each of which is configured to receive light and output a signal corresponding to the received light
Data Source
AI summary
According to an aspect, a detection device includes: an insulating substrate; a plurality of photoelectric conversion elements that are arranged in a detection area of the insulating substrate, and each of which is configured to receive light and output a signal corresponding to the received light; a first switching element that is provided for each photoelectric conversion element and includes a first semiconductor, a source electrode, and a drain electrode; and an inorganic insulating layer provided between the photoelectric conversion element and the first switching element in a normal direction of the insulating substrate.