Image Sensor Array with Dislocation Trapping for Broad Spectral Detection
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Solution Overview
Problem
Current solid-state imaging devices, particularly CCD technology, have limited spectral detection capabilities below 1 μm and suffer from high dark currents in short-wave infrared detection, which hinders their performance in applications like free-space laser communication requiring broad spectral detection.
Innovation Solution
The development of an image sensor array with a p-i-n structure and dislocation trapping technology, allowing for the formation of crystalline structures in trench patterns, which enhances epitaxy growth and reduces defects, enabling broad spectral detection from UV to long-infrared wavelengths and minimizing dark currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If CCD technology is used for imaging, then high resolution and mature CMOS fabrication are achieved, but spectral detection is limited to wavelengths below 1 μm
Solution Approach 1:
The patent segments the detector array into multiple regions with different semiconductor materials (e.g., Si for visible, InGaAs for infrared) to detect different spectral ranges simultaneously. Each segment is optimized for specific wavelength ranges, enabling broad spectral coverage from UV to long-infrared while maintaining high detection reliability in each region.
Solution Approach 2:
The patent employs composite material structures combining different semiconductor materials (Si, Ge, InGaAs, HgCdTe, PbS) in a single detector array. These composite materials enable the array to detect across a broad spectral range from UV to long-infrared wavelengths, overcoming the limitation of single-material detectors.
2Adaptability or versatility
If p-i-n photodiodes are used for near infrared detection, then detection at 1310 and 1550 nm wavelengths is achieved, but dark currents are seriously increased
Solution Approach 1:
The patent applies local quality optimization by using different material compositions and doping strategies in different regions of the photodiode structure. Specifically, optimized InGaAs material layers with controlled doping profiles are used in the detection region to reduce dark current while maintaining infrared detection capability at 1310 and 1550 nm wavelengths.
Solution Approach 2:
The patent changes key parameters including material composition (InGaAs with optimized In content), layer thickness, and doping concentrations to simultaneously achieve low dark current and high infrared detection efficiency. Temperature control parameters are also optimized to minimize thermal generation of dark current.
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 an image sensor array with improved spectral detection capabilities and reduced dark currents, enabling high-resolution imaging across a broad spectral range, enhancing performance in applications such as free-space laser communication.
Implementation Method 1
Detectors (a.k.a. photodiode or sensor pixel) especially of p/intrinsic/n (p-i-n) type conductivity have been studied extensively over the last decade for its application in optical communication
Implementation Method 2
enhances epitaxy growth and reduces defects
Data Source
AI summary
An image sensor array is disclosed. The image sensor array includes: a semiconductor substrate; a lateral photo detector structure over the semiconductor substrate, wherein the lateral photo detector structure has a dislocation trapping region protruding to the semiconductor substrate; and an insulating layer disposed over the lateral photo detector structure and further extending to a space between the lateral photo detector structure and the semiconductor substrate; wherein the lateral photo detector structure includes a first type region and a second type region having a polarity opposite to a polarity of the first type region, and the first type region extends at least along a portion of a boundary between an upside of the intrinsic region and the insulating layer. An associated manufacturing method is also disclosed.