Integrated Avalanche Photodiode Receiver Parasitic Reduction
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Solution Overview
Problem
High-speed photonic devices, such as avalanche photodiodes, face challenges in achieving both high responsivity and high bandwidth due to parasitic inductance and capacitance introduced by long bonding wires, which are exacerbated in compact, high-density multi-channel arrays where channel pitch is large, impacting RF performance.
Innovation Solution
A fully integrated photonic device is developed using a silicon-on-insulator (SOI) substrate with a buried oxide layer, incorporating an avalanche photodiode, capacitor, resistor, and silicon passive waveguides, with bonding pads, and a manufacturing process involving doping, oxide deposition, and metallization to minimize parasitic effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long bonding wire is used to connect pad and passive component, then device can be assembled, but parasitic inductance and capacitance increase impacting RF performance
Solution Approach 1:
The patent merges the avalanche photodiode, capacitor, resistor, and bonding pads into a single integrated device on one chip. This eliminates the need for separate bonding wires connecting discrete components, thereby removing the parasitic inductance and capacitance that would be introduced by long bonding wires while maintaining all necessary functional connections.
Solution Approach 2:
The patent extracts the passive components (capacitor and resistor) and the bonding pads from being separate discrete components and integrates them directly onto the same chip as the avalanche photodiode. This extraction from discrete assembly to integrated structure eliminates the harmful bonding wire connections.
2Ease of manufacture
If large channel pitch is used in multi-channel array, then manufacturing is easier, but bonding wire becomes extremely long causing increased parasitic effects
Solution Approach 1:
The patent combines multiple channels into a compact array where all components for each channel are integrated on the same chip. This merging eliminates the need for long bonding wires that would connect components across large channel pitches, reducing parasitic effects while maintaining manufacturability through monolithic integration.
3Device complexity
If surface illuminated device is used for high speed operation, then device structure is simple, but cannot achieve both high responsivity and high bandwidth simultaneously
Solution Approach 1:
The patent transitions from surface illumination to waveguide-based optical coupling, where light is guided through a three-dimensional waveguide structure to the photodiode active region. This dimensional change allows for better optical confinement and higher efficiency while maintaining compact integration, enabling both high responsivity and high bandwidth performance.
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 enables improved RF performance by reducing parasitic inductance and capacitance, allowing for high responsivity and bandwidth simultaneously, suitable for high-speed operations like 25 Gb/s and beyond, while maintaining a compact module design.
Implementation Method 1
an avalanche photodiode integrated with the SOI substrate
Implementation Method 2
implanting an implant region of the SOI substrate with n-type dopants to form a heavily-doped n-type contact layer; implanting the intrinsic Si multiplication layer with p-type dopants to form a p-type Si charge layer; implanting the intrinsic amorphous Si layer with p-type dopants to form a heavily-doped p-type contact layer
Implementation Method 3
depositing an intrinsic Ge layer
Data Source
AI summary
Various embodiments of a fully integrated avalanche photodiode receiver and manufacturing method thereof are described herein. A photonic device includes a silicon-on-insulator (SOI) substrate with a buried oxide (BOX) layer therein, an avalanche photodiode integrated with the SOI substrate, a capacitor integrated with the SOI substrate, a resistor integrated with the SOI substrate, and silicon passive waveguides as well as bonding pads integrated with the SOI substrate.