GOI Optical Sensor Structure for Mid-Infrared Field Confinement
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Solution Overview
Problem
Existing on-chip optical sensing devices are limited by their inability to effectively utilize mid-infrared light due to low field confinement capability and bulkiness, making them unsuitable for efficient gas or biomaterial detection.
Innovation Solution
A Ge-on-insulator (GOI) device with a germanium-based waveguide region and integrated light source and detection elements, capable of propagating and detecting mid-infrared light, is developed, utilizing a bolometric material layer to convert light into heat for detection, thereby enhancing sensitivity and bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If silicon-based waveguide is used for on-chip optical sensing, then device integration is achieved, but field confinement capability is low and mid-infrared sensing is limited
Solution Approach 1:
The patent changes the material parameter from silicon to germanium, which has different optical properties. Germanium's higher refractive index and lower absorption coefficient in the mid-infrared range enable both strong field confinement and effective mid-infrared sensing, resolving the contradiction between adaptability and reliability.
Solution Approach 2:
The patent employs a composite structure combining germanium layer with silicon dioxide insulation layer (Ge-on-SiO2 platform). This composite material approach leverages germanium's superior mid-infrared optical properties while using silicon dioxide for electrical insulation and structural support, achieving both field confinement and mid-infrared sensing capability.
2Measurement precision
If mid-infrared light is used for gas or biomaterial detection, then sensing accuracy is improved, but device size becomes bulky and cost increases
Solution Approach 1:
The patent merges the light source, waveguide, and detector into a single integrated on-chip device. By combining these previously separate components into one compact germanium-based platform, the system achieves high detection accuracy for mid-infrared sensing while minimizing device size and reducing overall system complexity.
Solution Approach 2:
The patent transitions from bulk optical components to planar waveguide structures, effectively moving the optical path into a two-dimensional integrated circuit format. This dimensional change enables mid-infrared sensing with high precision while dramatically reducing the device footprint from bulky three-dimensional components to a compact on-chip configuration.
3Reliability
If germanium layer is used in GOI structure, then field confinement capability is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent employs preliminary wafer bonding where a germanium layer is grown on a silicon wafer before bonding to the silicon dioxide substrate. This preliminary preparation of the germanium layer on a compatible substrate simplifies the overall manufacturing process by establishing a stable, pre-fabricated structure that maintains high field confinement capability while reducing processing complexity.
Solution Approach 2:
The patent uses a silicon dioxide layer as an intermediary between the germanium layer and the substrate. This intermediary layer facilitates the bonding process, provides electrical insulation, and enables the integration of germanium's superior optical properties with standard silicon-based manufacturing processes, thereby easing manufacturing while maintaining field confinement 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 GOI device enables ultra-small, high-field confinement optical sensing across a broad band, including mid-infrared ranges, with improved limit of detection and noise equivalent temperature difference, maximizing the extensibility of optical sensing applications.
Implementation Method 1
a bolometric material layer disposed on the GOI structure, whose resistance changes with heat generated as light is propagated from the germanium layer
Implementation Method 2
a GOI structure with a waveguide region comprising a germanium (Ge) layer; a light source element configured to generate light for the waveguide region
Data Source
AI summary
Various embodiments relate to an optical detection element and GOI (Ge-on-insulator) device for ultra-small on-chip optical sensing, and a manufacturing method of the same. According to various embodiments, the optical detection element and the GOI device may be implemented on a GOI structure comprising a germanium (Ge) layer, and the GOI device may be implemented to have an optical detection element. Specifically, the GOI device may include a GOI structure with a waveguide region comprising a germanium layer, a light source element configured to generate light for the waveguide region, and at least one optical detection element configured to detect light coming from the waveguide region. At least one slot configured to collect light from the light source element may be formed in the germanium layer in the waveguide region. The light source element may generate light so as to be coupled to the germanium layer in the waveguide region. The optical detection element may detect heat generated as light is propagated from the germanium layer.