Infrared Pixel Light-Receiving Structure for Leakage Suppression
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Solution Overview
Problem
Infrared sensors using semiconductor light receiving elements face challenges in improving sensitivity due to light leakage and color mixture between pixels, especially when a light-shielding film is not disposed between pixels.
Innovation Solution
The implementation of a first electrode layer with light-shielding properties between pixels on the light incident surface side of the photoelectric converter, and a stacked structure of a photoelectric conversion layer, first contact layer, and second contact layer with an insulating layer and transparent electrode layer added over the photoelectric converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent electrode layer is provided over the photoelectric conversion layer, then electrical contact is achieved, but light leakage between pixels occurs and sensitivity is reduced
Solution Approach 1:
The electrode layer is divided into pixel-separated segments with light-shielding films between adjacent pixels. This segmentation allows each pixel electrode to maintain electrical contact functionality while the intervening light-shielding films prevent light leakage and color mixture between adjacent pixels, resolving the contradiction between electrical contact and light leakage prevention.
Solution Approach 2:
Different regions of the electrode structure are assigned different properties: the electrode material in pixel regions maintains transparency for electrical contact, while the light-shielding film regions provide opacity to block light leakage. This local differentiation of properties allows simultaneous achievement of electrical contact and light leakage prevention.
2Reliability
If the first contact layer thickness is increased to improve electrical contact, then contact reliability improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The contact structure uses a composite of the first contact layer and light-shielding film materials that together provide both electrical contact functionality and light shielding. This composite approach achieves reliable electrical contact without requiring excessive thickness of the first contact layer, thereby reducing manufacturing complexity.
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
This configuration enhances sensitivity by reducing light leakage and eliminating the need for a transparent electrode, while also allowing for a thinner first contact layer, thereby improving the overall performance of the infrared sensor.
Implementation Method 1
a first electrode layer that is provided between the plurality of pixels on light incident surface side of the photoelectric converter, and has a light-shielding property
Implementation Method 2
a photoelectric converter that is provided as a layer common to the plurality of pixels, and contains a compound semiconductor material
Data Source
AI summary
A first light receiving element according to an embodiment of the present disclosure includes a plurality of pixels, a photoelectric converter that is provided as a layer common to the plurality of pixels, and contains a compound semiconductor material, and a first electrode layer that is provided between the plurality of pixels on light incident surface side of the photoelectric converter, and has a light-shielding property.