Stacked Pixel Image Sensor Layout for LED Flicker Reduction
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Solution Overview
Problem
Conventional semiconductor image sensors face issues with flickering images when not synchronized with pulsing light sources, such as LED devices, and have difficulty controlling pixels due to a metal grid that blocks light, leading to suboptimal performance in applications like automotive surveillance.
Innovation Solution
A semiconductor structure with a trench isolation dividing the substrate into sensing units, each comprising a first and second pixel with overlapping configurations, along with gate electrodes and a trench isolation structure to improve image sensor performance, allowing for better light collection and reduced flickering effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor image sensors are used, then they can detect light, but they experience flickering issues with LED light sources and have light blocked by metal grids
Solution Approach 1:
The image sensor is divided into multiple pixels with different gate electrode configurations. Specifically, first pixels have gate electrodes oriented in a first direction while second pixels have gate electrodes oriented in a second direction perpendicular to the first direction. This segmentation allows different pixel regions to capture light from different LED pulsing patterns, and through pixel binning, the flickering effects are averaged out to produce stable images.
2Productivity
If conventional image sensors are used, then they can capture images, but metal grids block light and complicate pixel control
Solution Approach 1:
The patent removes the conventional metal grid structure that blocks light and complicates control. Instead, isolated pixel regions are formed without requiring metal grids for isolation or control, thereby eliminating light blocking while simplifying the pixel control architecture.
Solution Approach 2:
The patent introduces a new dimension of control by orienting gate electrodes in two perpendicular directions (first direction and second direction) across different pixel regions. This dimensional approach to gate electrode orientation provides enhanced control over light capture patterns without requiring traditional metal grid structures, thereby improving light collection efficiency while maintaining simplified pixel control.
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 proposed structure enhances image sensor performance by minimizing flickering and improving light control, ensuring more accurate and stable image capture, particularly in applications with pulsing light sources.
Implementation Method 1
These devices utilize an array of pixels (which may include photodiodes and transistors) to detect radiation using photogeneration of electron-hole pairs.
Data Source
AI summary
An image sensor device includes a semiconductor substrate having a first side, and a trench isolation structure dividing the substrate into sensing units. Each sensing unit includes a first gate electrode and a second gate electrode disposed on the first side, and a first pixel and a second pixel extending into the substrate and disposed between the first and second gate electrodes from a top view perspective. The first pixel is disposed under the second pixel and electrically connected to the first gate electrode, and the second pixel is electrically connected to the second gate electrode. A method of manufacturing a semiconductor structure includes forming a trench isolation in a semiconductor substrate; forming a first pixel in the substrate; forming a second pixel in the substrate over the first pixel; forming a first gate structure over the substrate; and forming a second gate structure over the second pixel.