Subpixel Photodetector Segmentation for Leakage and Cross-Talk Reduction
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Solution Overview
Problem
Photodetectors in various applications face performance degradation due to leakage current, dark current, electrical/optical cross-talk, and high power consumption, especially when used in single or array configurations for detecting optical signals beyond visible wavelengths.
Innovation Solution
A photo-detecting apparatus utilizing a germanium-based light absorption material supported by a semiconductor substrate, with strategically doped regions and metal lines to control photo-generated carriers, enabling efficient absorption of near-infrared or short-wave infrared light, and incorporating a pixel structure with subpixels and isolation regions to minimize leakage and cross-talk, while optimizing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photodetectors are used in single or array configurations to detect optical signals beyond visible wavelengths, then the detection capability for near-infrared or short-wave infrared light is improved, but leakage current, dark current, electrical/optical cross-talk, and power consumption increase
Solution Approach 1:
The photodetector is divided into multiple pixels, and each pixel is further segmented into N subpixels (where N≥2). Each subpixel includes a detection region and two switches. This segmentation isolates the detection regions from each other, reducing electrical and optical cross-talk between adjacent detection elements while maintaining the ability to detect near-infrared and short-wave infrared light across the array configuration.
Solution Approach 2:
Each subpixel is equipped with two switches that can independently control the detection regions. This local control mechanism allows for selective activation and deactivation of specific subpixels, enabling the system to minimize leakage current and dark current by keeping non-active regions in a high-impedance state while maintaining detection capability in active regions.
2Adaptability or versatility
If photodetectors are used in single or array configurations to detect optical signals beyond visible wavelengths, then the detection capability for near-infrared or short-wave infrared light is improved, but electrical/optical cross-talk increases
Solution Approach 1:
The photodetector is divided into multiple pixels, and each pixel is further segmented into N subpixels (where N≥2). Each subpixel includes a detection region and two switches. This segmentation isolates the detection regions from each other, reducing electrical and optical cross-talk between adjacent detection elements while maintaining the ability to detect near-infrared and short-wave infrared light across the array configuration.
Solution Approach 2:
The harmful cross-talk between adjacent pixels is extracted and eliminated by introducing isolation regions between pixels. Additionally, the two-switch configuration within each subpixel allows for electrical isolation of detection regions, effectively removing the cross-talk pathway while preserving the detection function.
3Adaptability or versatility
If photodetectors are used in single or array configurations to detect optical signals beyond visible wavelengths, then the detection capability for near-infrared or short-wave infrared light is improved, but power consumption increases
Solution Approach 1:
The two switches in each subpixel enable periodic or selective activation of detection regions. Instead of continuously powering all detection regions, the system can activate only the necessary subpixels for current measurement, reducing overall power consumption while maintaining detection capability for near-infrared and short-wave infrared light when needed.
Solution Approach 2:
Each subpixel is equipped with two switches that can independently control the detection regions. This local control mechanism allows for selective activation and deactivation of specific subpixels, enabling the system to minimize power consumption by keeping non-active regions in a high-impedance state while maintaining detection capability in active regions.
4Reliability
If pixel structure with subpixels and isolation regions is implemented, then leakage current and cross-talk are reduced, but device complexity increases
Solution Approach 1:
The isolation regions are merged into the pixel structure itself, forming an integrated design where pixels contain multiple subpixels with built-in isolation. This merging approach reduces the need for separate isolation structures and simplifies the overall fabrication process while effectively reducing leakage current and cross-talk.
Solution Approach 2:
The two switches in each subpixel serve multiple functions: they control the detection regions, provide electrical isolation, enable selective activation, and reduce power consumption. This multi-functionality reduces the need for additional components that would otherwise be required to achieve the same effects, thereby limiting the increase in device 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
The solution provides high demodulation contrast, low leakage and dark currents, reduced power consumption, and efficient processing of optical signals across multiple wavelengths, suitable for time-of-flight applications, with improved chip size miniaturization and reduced electrical/optical cross-talk.
Implementation Method 1
A first germanium-based light absorption material is supported by the semiconductor substrate and configured to absorb a first optical signal having a first wavelength greater than 800 nm
Data Source
AI summary
A photo-detecting apparatus is provided. The photo-detecting apparatus includes at least one pixel, and each pixel includes N subpixels, wherein each of the subpixels comprises a detection region, two first conductive contacts, wherein the detection region is between the two first conductive contacts, wherein N is a positive integer and is ≥2.