Vertical Germanium Photodiode Layout for Higher-Speed Optical Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The speed of data transfer through optical fibers is limited by the electro-optical and opto-electric converters, which struggle to efficiently convert light signals into electric signals due to limitations in modulators and demodulators.
Innovation Solution
A vertical photodiode with an active area where all contacting areas are shifted above the active region, comprising a lower intrinsic germanium portion and an upper doped germanium portion, in contact with doped silicon regions, and an insulating trench, allowing for efficient conversion of light signals into electric signals through a waveguide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional photodetectors are used, then light signals can be converted into electric signals, but the data transfer speed is limited due to inefficiencies in electro-optical and opto-electric converters
Solution Approach 1:
The patent changes the physical and material parameters of the photodetector by using a vertical configuration with mixed silicon-germanium materials, different doping types (n-type and p-type), and specific layer structures. These parameter changes enable higher bandwidth operation and improved conversion efficiency, achieving data transfer speeds up to 25 Gbps while maintaining reliable signal conversion.
2Manufacturing precision
If contacting areas are positioned above the active area, then manufacturing precision is improved, but device complexity increases due to the need for lateral contacts and insulating trenches
Solution Approach 1:
The patent transitions from a conventional planar contact configuration to a vertical configuration where contacts are positioned laterally adjacent to the active area rather than directly above it. This dimensional change in contact placement simplifies the manufacturing process by avoiding the need for precise vertical alignment through multiple lithography steps, while the lateral contact structure with insulating trenches manages the increased spatial 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
This configuration enhances the frequency of the converter, enabling higher data transfer speeds, potentially up to 25 Gbps, by minimizing manufacturing inaccuracies and maintaining light signal confinement within the active area.
Implementation Method 1
converters of light signals into electric signals or opto-electric converters
Data Source
AI summary
A vertical photodiode includes an active area. The contacting pads for the diode terminals are laterally shifted away from the active area so as to not be located above or below the active area. The active area is formed in a layer of semiconductor material by a lower portion of a germanium area that is intrinsic and an upper portion of the germanium area that is doped with a first conductivity type. The vertical photodiode is optically coupled to a waveguide formed in the layer of semiconductor material.