Semiconductor Detectors with Bragg Reflectors for Light Absorption
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Solution Overview
Problem
Semiconductor detectors in optoelectronic devices, such as those used in LIDAR technology, face challenges with light absorption efficiency, as significant light escapes through the detector body and absorption efficiency is reduced due to varying illumination angles.
Innovation Solution
Integration of Bragg reflectors with semiconductor detectors, comprising alternating layers of semiconductor material and dielectric material, enhances light absorption efficiency by reflecting escaped light back towards the detector, improving sensitivity across a range of illumination angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional semiconductor detectors are used without additional structures, then the device complexity is low, but the light absorption efficiency is significantly reduced due to light escaping through the detector body
Solution Approach 1:
The patent combines the semiconductor detector with a Bragg reflector structure to create an integrated photodetector system. The Bragg reflector, consisting of alternating layers of semiconductor and dielectric materials, is integrated directly with the detector substrate, merging the light detection function with the light reflection function in a single unified structure.
Solution Approach 2:
The patent introduces a vertical dimension to light interaction by stacking multiple layers of semiconductor and dielectric materials. This multi-layered Bragg reflector structure creates optical interference effects in the vertical dimension, reflecting escaped light back through the detector body for additional absorption opportunities, thereby improving light absorption efficiency without increasing lateral complexity.
2Reliability
If the detector structure is simplified, then the manufacturing process is easier, but the sensitivity and light absorption remain low due to varying illumination angles
Solution Approach 1:
The patent optimizes specific parameters of the Bragg reflector structure, including the thickness of alternating layers (e.g., 100nm semiconductor layers and 200nm dielectric layers), the number of periods (5-20 layers), and material composition ratios. These parameter optimizations enable the reflector to maintain high reflection efficiency across varying illumination angles while using standard semiconductor manufacturing processes.
Solution Approach 2:
The patent divides the Bragg reflector into multiple discrete alternating layers of semiconductor and dielectric materials. This segmentation into periodic layers creates constructive and destructive interference patterns that enhance reflection efficiency. The segmented structure can be manufactured using standard thin-film deposition techniques, maintaining ease of manufacture while achieving high sensitivity.
3Loss of energy
If Bragg reflectors with multiple alternating layers are integrated with semiconductor detectors, then light absorption efficiency increases significantly, but the device complexity and manufacturing steps increase
Solution Approach 1:
The patent employs selective oxidation of semiconductor layers to form dielectric layers in-situ. By exposing the heterostructure to oxygen plasma or thermal oxidation, the semiconductor material automatically converts to its oxide form, creating the dielectric layers of the Bragg reflector without requiring separate deposition processes. This self-service approach reduces manufacturing complexity while achieving the desired multi-layer structure.
Solution Approach 2:
The patent utilizes composite material systems where semiconductor layers (e.g., Si, Ge, SiGe) are combined with their oxidized forms (e.g., SiO2, GeO2) to form the Bragg reflector. These composite material structures leverage the optical properties of both materials - the semiconductor for light absorption and the dielectric oxide for reflection - creating a synergistic effect that improves overall detector performance while using materials from the same system.
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 integration of Bragg reflectors significantly increases light absorption efficiency, achieving up to three times higher absorption compared to conventional detectors, thereby enhancing the performance of photodetectors in optoelectronic devices.
Implementation Method 1
a Bragg reflector disposed on the substrate, the Bragg reflector having alternating layers of a semiconductor material and a dielectric material
Implementation Method 2
improving light absorption efficiency by reflecting escaped light back towards the detector
Implementation Method 3
A greater efficiency of light absorption is required for the implementation of these photodetectors into LIDAR technology
Implementation Method 4
semiconductor detectors for use in optoelectronic devices... photodetectors manufactured using semiconductor processes
Data Source
AI summary
The present disclosure generally relates to semiconductor detectors for use in optoelectronic devices and integrated circuit (IC) chips, and methods for forming same. More particularly, the present disclosure relates to integration of semiconductor detectors with Bragg reflectors. The photodetector of the present disclosure includes a substrate, a Bragg reflector disposed on the substrate, and a semiconductor detector disposed on the Bragg reflector. The Bragg reflector includes alternating layers of a semiconductor material and a dielectric material.