Suspended LED and Photodetector Monolithic Integration
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Solution Overview
Problem
Existing technologies face challenges in monolithically integrating light-emitting diodes (LEDs), optical waveguides, and photodetectors on the same chip, leading to complexity and interference issues, which hinders the development of planar photon devices for optical communication and sensing.
Innovation Solution
A device is fabricated with a suspended LED, optical waveguide, and photodetector on a silicon-based nitride wafer, where the LED and photodetector are connected via an optical waveguide, and the structure includes a p-n junction, step-shaped stages, and isolation trenches to prevent interference, using Ni/Au electrodes and anisotropic silicon etching techniques for integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LED, optical waveguide and photodetector are integrated on the same chip, then device functionality and light transmission efficiency are improved, but device complexity and mutual interference increase
Solution Approach 1:
The device is segmented into three functionally independent modules (LED, optical waveguide, photodetector) that are spatially separated and optically coupled. This segmentation allows each component to operate independently with optimized performance while reducing mutual interference through physical isolation, resolving the contradiction between integration benefits and complexity increases.
Solution Approach 2:
The optical waveguide acts as an intermediary component that couples the LED and photodetector through optical fields rather than direct electrical or physical contact. This intermediary approach enables efficient light transmission while isolating the active components, thereby improving light transmission efficiency without proportionally increasing device complexity.
2Adaptability or versatility
If LED, optical waveguide and photodetector are integrated on the same chip, then device functionality is improved, but fabrication complexity increases
Solution Approach 1:
The nitride material layer serves multiple functions simultaneously: it acts as the active layer for LED light emission, as the core material for optical waveguide transmission, and as the sensitive layer for photodetector detection. This multi-functionality of a single material system enables integrated device fabrication using unified nitride material processing techniques, thereby improving device functionality without proportionally increasing fabrication complexity.
3Reliability
If suspended structure is used for LED and photodetector, then optical performance is improved, but fabrication difficulty increases
Solution Approach 1:
The LED and photodetector are extracted from the silicon substrate and suspended above it, with only their essential nitride material layers retained. This extraction creates the suspended structure that improves optical performance by reducing substrate interference and enhancing light extraction efficiency, while the simplified suspended geometry actually reduces fabrication difficulty compared to complex integrated mounting structures.
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 approach simplifies the fabrication process, reduces complexity, and achieves a planar photon monolithically integrated device with reduced mutual interference, enabling efficient light transmission and detection for optical communication and sensing applications.
Implementation Method 1
the light emitted by the LED is laterally coupled to the optical waveguide
Implementation Method 2
transmitted over the optical waveguide
Implementation Method 3
detected by the photodetector at the other end of the optical waveguide
Implementation Method 4
based on the high refractive index property of the nitride material
Data Source
AI summary
An integrated device and a fabrication method thereof are provided. In the device, by using various anisotropic silicon etching techniques, the silicon substrate layer and the expitaxial buffer layer under the device structure are removed, an ultra-thin device monolithically integrated with a suspended LED, an optical waveguide and a photodetector is obtained by further using the nitride back thinning etching technique. In the device, the light source, the optical waveguide and the photodetector are integrated on the same chip. The light emitted by the LED is laterally coupled to the optical waveguide, transmitted over the optical waveguide, and detected by the photodetector at the other end of the optical waveguide, thereby achieving a planar photon monolithically integrated device which is applied in the fields of optical transmission and optical sensing.