Trench Avalanche Photodiode Reducing Carrier Recombination
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Solution Overview
Problem
Conventional avalanche photodiodes have high signal loss due to longer carrier pathways, leading to photon recombination, and require thick photosensitive materials that are expensive and challenging to integrate with other circuit elements.
Innovation Solution
The development of avalanche photodiodes with a trench structure and epitaxial growth of semiconductor materials, creating a three-dimensional carrier path and using reflective isolation to reduce recombination and enhance integration with other devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional two-dimensional carrier pathways are used, then the structure is simple, but the carrier path length increases leading to high signal loss and photon recombination
Solution Approach 1:
The patent transitions from conventional two-dimensional carrier pathways to a three-dimensional carrier collection architecture. The trench structure with semiconductor material lining the sidewalls and bottom creates multiple collection paths in vertical and lateral dimensions, significantly shortening the effective carrier transport distance and reducing recombination losses while maintaining structural feasibility.
Solution Approach 2:
The photosensitive material is segmented into multiple regions with different doping types (first dopant type, second dopant type, and intrinsic regions) arranged in a three-dimensional configuration within the trench. This segmentation creates multiple carrier collection zones and pathways, enabling efficient charge separation and collection while minimizing recombination.
2Reliability
If the photosensitive material is made very thick to increase sensitivity, then quantum efficiency improves, but manufacturing cost and integration difficulty increase
Solution Approach 1:
Instead of increasing photosensitive material thickness in a single dimension, the patent employs a three-dimensional trench structure that provides extended light interaction paths through vertical and lateral dimensions. This approach achieves high quantum efficiency without requiring excessive material thickness, thereby reducing manufacturing complexity and integration challenges.
Solution Approach 2:
The trench structure is nested within the substrate, with multiple semiconductor material layers (first dopant type, second dopant type, intrinsic regions) arranged concentrically and hierarchically. This nested configuration maximizes the photosensitive volume and light interaction path within a compact footprint, achieving high quantum efficiency without increasing overall device size or manufacturing 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 design increases sensitivity and reduces signal loss by shortening the carrier path and improving integration, while maintaining high responsivity across various wavelengths.
Implementation Method 1
An avalanche photodiode (APD) is a highly sensitive semiconductor photodiode that exploits the photoelectric effect to convert light into electricity.
Implementation Method 2
an isolation structure comprising reflective material surrounding the trench, and remotely positioned from the intrinsic photosensitive semiconductor material
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to an avalanche photodiode and methods of manufacture. The structure includes: a substrate material having a trench with sidewalls and a bottom composed of the substrate material; a first semiconductor material lining the sidewalls and the bottom of the trench; a photosensitive semiconductor material provided on the first semiconductor material; and a third semiconductor material provided on the photosensitive semiconductor material.