Semiconductor Image Sensor Pixel Structure for Optical Crosstalk
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Solution Overview
Problem
Existing semiconductor image sensors face challenges with quantum efficiency and optical crosstalk, particularly as sensor sizes decrease, leading to increased sensitivity to crosstalk noise.
Innovation Solution
The implementation of a semiconductor device design that includes a first light sensing unit and a second light sensing unit, with the first light sensing unit receiving less radiation and surrounded by second light sensing units, and the use of isolation structures and reflective layers to reduce crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the sensor size is decreased to improve portability and reduce cost, then the device becomes more compact, but optical crosstalk between pixels increases
Solution Approach 1:
The sensor array is divided into first pixels and second pixels with different structural configurations. First pixels have a first photoelectric conversion layer while second pixels have a second photoelectric conversion layer, creating segmented functional regions that reduce optical crosstalk while maintaining compact sensor size.
Solution Approach 2:
Different regions of the sensor are given different local properties: first pixels are optimized for certain wavelength ranges with their specific photoelectric conversion layer structure, while second pixels are optimized for different wavelength ranges. This local differentiation reduces optical interference between adjacent pixels.
2Reliability
If the quantum efficiency is improved by increasing light absorption, then more photons are converted to electrons, but optical crosstalk between adjacent pixels increases
Solution Approach 1:
The photoelectric conversion structure is segmented into different layers for different pixel types. First pixels use a first photoelectric conversion layer while second pixels use a second photoelectric conversion layer, allowing each to be optimized for its specific function while minimizing cross-interference through structural separation.
Solution Approach 2:
The sensor employs asymmetric pixel design where first pixels and second pixels have different structural configurations and photoelectric conversion properties. This asymmetry allows optimization of quantum efficiency for each pixel type while reducing optical crosstalk through differentiated light absorption characteristics.
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 design enhances light absorption efficiency by reducing crosstalk interference, thereby improving the sensitivity of the first light sensing units, especially in low-light conditions.
Implementation Method 1
semiconductor image sensors utilize an array of pixels in a substrate, including photodiodes and transistors that can absorb radiation projected toward the substrate and convert the sensed radiation into electrical signals
Implementation Method 2
disposing a reflective layer above the first light sensing unit
Data Source
AI summary
A semiconductor device includes a first type of light sensing units, where each instance of the first type of light sensing units is operable to receive a first amount of radiation; and a second type of light sensing units, where each instance of the second type of light sensing units is operable to receive a second amount of radiation, and the second type of light sensing units is arranged in an array with the first type of light sensing units to form a pixel sensor. The first amount of radiation is smaller than the second amount of radiation, and at least a first instance of the first type of light sensing units is adjacent to a second instance first type of light sensing unit.