Geiger-Mode Avalanche Diodes With Textured Photon-Mixing Structures
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Solution Overview
Problem
Conventional photodetector devices struggle to detect both very dim and very bright objects with high temporal accuracy due to limited dynamic range and high power consumption, especially in bright ambient light conditions, and Geiger-mode photodiodes face challenges with low Photon Detection Probability (PDP) and timing resolution issues.
Innovation Solution
The photodetector devices incorporate Geiger-mode photodiodes with textured and diffractive optical structures to increase photon absorption probability, using isolation regions and optical structures like inverted pyramidal arrays to enhance sensitivity and dynamic range, while maintaining low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional photodetector devices are used to detect both very dim and very bright objects, then the dynamic range is limited, but the power consumption increases significantly
Solution Approach 1:
The photodetector device is divided into multiple photodiodes operating in different modes: Geiger-mode photodiodes for detecting dim objects (single photon detection) and linear-mode photodiodes for detecting bright objects (analog signal detection). This segmentation allows the system to handle a wide dynamic range by selecting the appropriate detection mode for each object brightness level, thereby extending the overall dynamic range without proportionally increasing power consumption across all detection channels.
2Measurement precision
If higher optical emission power is used to illuminate large field of view and receive recognizable echo signal, then the detection capability is improved, but the power consumption increases
Solution Approach 1:
The system changes the detection parameter from analog signal strength to time of flight measurement. By using Geiger-mode photodiodes that detect single photons and measuring the time delay between transmitted and received light pulses, the system can detect dim echo signals from large field of view without increasing optical emission power. This parameter change enables high detection capability while maintaining low power consumption.
3Measurement precision
If Geiger-mode photodiodes are used to detect single photons, then the sensitivity is improved, but the photon detection probability decreases
Solution Approach 1:
The patent introduces a spatial dimension by positioning the Geiger-mode photodiode at an angle relative to the incident light path, rather than having it perpendicular to the light. This angular positioning, combined with the textured region that increases optical path length, allows photons to travel a longer distance through the semiconductor material, increasing the probability of photon absorption and detection while maintaining the high sensitivity of Geiger-mode operation.
4Measurement precision
If textured region with optical structures is added to increase optical path lengths, then the quantum efficiency is improved, but the device complexity increases
Solution Approach 1:
The textured region incorporates curved or non-planar optical structures (such as inverted pyramidal arrays or spherical bumps) on the surface of the semiconductor material. These curved structures increase the optical path length by causing light to reflect multiple times within the material, thereby improving quantum efficiency. The curvature is achieved through standard semiconductor fabrication techniques, keeping the added complexity manageable while delivering significant performance improvement.
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 high quantum efficiency and sensitivity, enabling accurate detection of both dim and bright objects with improved temporal responsivity and reduced power consumption, and enhances photon detection probability across the photodiodes.
Implementation Method 1
A textured region coupled to the semiconductor material layer and comprising optical structures positioned to interact with and configured to increase optical path lengths of the incident photons in the semiconductor material layer
Implementation Method 2
optical structures positioned to interact with and configured to increase optical path lengths of the incident photons
Implementation Method 3
at least one photodiode in the semiconductor material layer that is configured to be biased beyond a breakdown voltage thereof to generate respective electrical signals responsive to detection of incident photons
Implementation Method 4
Geiger-mode avalanche diodes... at least one photodiode in the semiconductor material layer that is configured to be biased beyond a breakdown voltage
Data Source
Figure 1A~1B
Figure 1C~2A
Figure 2B~3
AI summary
A photodetector device includes a semiconductor material layer and at least one photodiode in the semiconductor material layer. The at least one photodiode is configured to be biased beyond a breakdown voltage thereof to generate respective electrical signals responsive to detection of incident photons. The respective electrical signals are independent of an optical power of the incident photons. A textured region is coupled to the semiconductor material layer and includes optical structures positioned to interact with the incident photons in the detection thereof by the at least one photodiode. Two or more photodiodes may define a pixel of the photodetector device, and the optical structures may be configured to direct the incident photons to any of the two or more photodiodes of the pixel.