Hybrid Bonded P-i-n Image Sensor Array for Dark Current Reduction
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Solution Overview
Problem
Current CCD-based imaging devices have limited spectral detection capabilities, high dark currents, and require large landing areas for indium bumps, which hinder their performance in applications like free space laser communication and near-infrared detection.
Innovation Solution
A p-i-n image sensor array with contact implant regions and hybrid bonding technology is developed, using smaller contact implant regions and eliminating the need for large landing areas, thereby reducing dark current and enhancing spectral detection from UV to long-infrared wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If indium bump structures are used for bonding, then bonding strength is achieved, but dark current increases and landing area becomes large
Solution Approach 1:
The patent extracts and removes the indium bump structure from the bonding interface, replacing it with a direct hybrid bonding approach between semiconductor surfaces. This elimination of the indium layer removes the source of dark current while maintaining bonding functionality through direct material contact and diffusion bonding mechanisms.
Solution Approach 2:
The patent introduces a carefully engineered interface layer or transition structure that mediates between the bonding surfaces, enabling strong adhesion without requiring indium bumps. This intermediary structure facilitates direct bonding while preventing the formation of dark current paths that would otherwise be generated by indium-semiconductor interfaces.
2Strength
If indium bump structures are used for bonding, then bonding strength is achieved, but landing area becomes large
Solution Approach 1:
The patent removes the indium bump structure that required large landing areas, replacing it with a planar hybrid bonding interface. This extraction eliminates the need for large protruding bumps and their associated landing pads, significantly reducing the footprint while maintaining bonding strength through distributed contact areas.
Solution Approach 2:
The patent transitions from a three-dimensional bump structure requiring large planar landing areas to a two-dimensional planar bonding interface. By changing the bonding geometry from vertical bumps to horizontal surfaces, the effective bonding area is distributed across a smaller footprint, reducing the overall landing area requirement.
3Ease of manufacture
If CCD technology is used for imaging, then mature fabrication is achieved, but spectral detection range is limited below 1 μm
Solution Approach 1:
The patent employs composite material structures combining different semiconductor layers with complementary spectral responses. By stacking materials such as silicon for visible/NIR detection with other semiconductor compounds for SWIR detection, the device achieves broad spectral coverage from UV through long-wavelength infrared while utilizing mature CMOS fabrication processes for each layer.
Solution Approach 2:
The patent divides the imaging device into multiple detector layers or regions, each optimized for specific wavelength ranges. This segmentation allows each segment to be fabricated using appropriate materials and processes while maintaining overall compatibility with CMOS technology, enabling multi-spectral detection capabilities beyond what a single material could provide.
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 broad spectral detection capabilities and minimizes dark current, improving the overall performance and resolution of the image sensor array, particularly in near-infrared wavelengths, while ensuring strong bonding without the drawbacks of existing indium bump structures.
Implementation Method 1
p-i-n image sensor array... broad spectral detection capabilities... near-infrared detection
Implementation Method 2
hybrid bonding technology... ensuring strong bonding
Data Source
AI summary
A sensor device is disclosed. The sensor device include: a detector having a contact formation region; an insulating layer disposed over the detector; a conductive pad disposed over the insulating layer opposite to a side of the detector; a contact plug formed in the insulating layer for electrically coupling the contact implant region and the conductive pad; and a read-out integrated circuit bonded to the insulating layer through the conductive pad. An image sensor array and a manufacturing method of a sensor device are also disclosed.