Lateral Composition Gradient Photodetector for LIDAR
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
LIDAR systems require photodetectors capable of operating at longer wavelengths, such as 1.5 microns, to improve the signal-to-noise ratio, particularly in applications like autonomous vehicles, where existing germanium photodetectors face challenges in absorbing infrared wavelengths effectively.
Innovation Solution
A photodetector structure is developed with a semiconductor alloy layer that includes a p-type and n-type doped region forming a p-n junction, where the semiconductor alloy composition is laterally graded through a recrystallization process, allowing for enhanced absorption of longer wavelengths by varying the alloy component ratio across the active region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If germanium photodetectors are used in conventional LIDAR systems, then they provide good infrared absorption, but they cannot effectively absorb longer wavelengths (1.5 microns) required for improved signal-to-noise ratio
Solution Approach 1:
The patent applies local quality by creating a laterally graded semiconductor alloy composition within the photodetector layer. The alloy composition varies from one side to the other, with different regions having different bandgap energies tailored to absorb specific wavelengths. This allows the single photodetector structure to handle multiple wavelengths effectively, including the 1.5 micron range, thereby improving signal-to-noise ratio while maintaining adaptability.
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 graded semiconductor alloy photodetector improves the absorption of laser light at longer wavelengths, enabling LIDAR systems to operate at higher power with an enhanced signal-to-noise ratio, effectively addressing the limitations of existing germanium photodetectors.
Implementation Method 1
the semiconductor alloy has a composition that is laterally graded from the first side to the second side... improves the absorption of laser light at longer wavelengths
Implementation Method 2
Each germanium photodetector converts incident reflected pulses received from the target into current as photons of electromagnetic radiation are absorbed in the germanium
Data Source
AI summary
Structures including a photodetector and methods of fabricating such structures. The photodetector is positioned over the top surface of the substrate. The photodetector includes a portion of a semiconductor layer comprised of a semiconductor alloy, a p-type doped region in the portion of the semiconductor layer, and an n-type doped region in the portion of the semiconductor layer. The p-type doped region and the n-type doped region converge along a p-n junction. The portion of the semiconductor layer has a first side and a second side opposite from the first side. The semiconductor alloy has a composition that is laterally graded from the first side to the second side of the portion of the semiconductor layer.