Patterned Semiconductor Polarizer for Low-Noise Image Sensing
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Solution Overview
Problem
Backside illuminated image sensors face challenges in achieving high photo-electric conversion efficiency, sensitivity, and low noise as component sizes scale down, requiring innovative solutions to enhance sensing efficiency and accuracy.
Innovation Solution
A photosensitive device comprising a semiconductor substrate with a patterned semiconductor polarizer, a photodiode, and a reflective grid element, where the patterned semiconductor polarizer filters incident light by allowing only expected polarization directions to pass, and the reflective grid element reflects light to increase sensing efficiency and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the component size of backside illuminated image sensor is scaled down, then the device becomes more compact and integration is improved, but the photo-electric conversion efficiency and sensitivity deteriorate
Solution Approach 1:
The semiconductor substrate is divided into a sensing region with photodiodes and a polarizing region with patterned semiconductor polarizers. This segmentation allows the polarizers to be positioned specifically in the light incident path without interfering with the photodiode structure, maintaining photo-electric conversion efficiency while enabling polarization filtering in the scaled-down device
Solution Approach 2:
The patterned semiconductor polarizer introduces local quality variation by creating regions with different optical properties (polarization filtering) within the semiconductor substrate. The polarizer pattern is strategically placed in the polarizing region to selectively filter light based on polarization direction, enhancing sensitivity without requiring larger component size
2Ease of manufacture
If conventional structures are used in backside illuminated image sensor, then manufacturing is simpler, but sensing efficiency and accuracy are insufficient
Solution Approach 1:
The patent merges the polarizer function with the semiconductor substrate by forming the patterned semiconductor polarizer directly in the substrate using semiconductor fabrication processes. This integration eliminates the need for separate polarizer components and complex assembly steps, maintaining manufacturing simplicity while significantly enhancing sensing accuracy through polarization filtering
Solution Approach 2:
The semiconductor substrate serves multiple functions: it acts as both the structural base for photodiodes and the medium for forming patterned semiconductor polarizers. This multi-functionality allows the same substrate to provide both mechanical support and optical polarization filtering, improving sensing accuracy without adding separate manufacturing processes
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 significantly enhances the sensing efficiency and accuracy of the photosensitive device by filtering unwanted light and reducing interference from adjacent pixels, thereby meeting the demands of high sensitivity and low noise in smaller component sizes.
Implementation Method 1
The semiconductor substrate has a patterned semiconductor polarizer. The patterned semiconductor polarizer can filter an incident light
Implementation Method 2
a reflective grid element reflects light to increase sensing efficiency and accuracy
Implementation Method 3
Backside illuminated image sensor has high efficiency... high quantum efficiency
Data Source
AI summary
A photosensitive device includes a semiconductor substrate and a photodiode. The semiconductor substrate has a patterned semiconductor polarizer having a semiconductor surface. The photodiode is in the semiconductor substrate.