Optical Waveguide Semiconductor Device Leakage Current Reduction
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Solution Overview
Problem
Integrated semiconductor optical devices face current leakage issues due to contact between the optical active device and the optical waveguide, leading to degradation in optical active device characteristics.
Innovation Solution
Incorporating a high resistance layer or a semi-insulating semiconductor material between the optical active device and the optical waveguide to prevent current flow, which can be achieved by forming a laminated structure with specific cladding and guiding layers and epitaxially growing a high resistance layer to block current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the optical waveguide portion is placed adjacent to the optical active device portion without isolation, then the device integration is simplified and manufacturing is easier, but current leakage occurs from the optical active device to the optical waveguide through the cladding layer
Solution Approach 1:
A high resistance layer is introduced as an intermediary between the optical active device portion and the optical waveguide portion. This layer extends across the interface region and prevents current leakage while maintaining the adjacent placement configuration for simplified integration.
Solution Approach 2:
The high resistance layer is selectively positioned only at the critical interface region where current leakage occurs, rather than isolating the entire devices. This localized approach prevents leakage while maintaining ease of manufacture through simple adjacent placement.
2Reliability
If a separating trench with semi-insulating semiconductor layer is formed between the semiconductor laser and modulator, then electrical separation is achieved, but the device structure becomes more complex
Solution Approach 1:
The invention extracts only the essential current-blocking function from the complex separating trench structure. By using a high resistance layer that can be integrated into the existing cladding layer configuration, the solution achieves electrical separation without requiring deep trench formation or additional semi-insulating layers.
Solution Approach 2:
The invention changes the electrical parameter (resistivity) of the cladding layer by forming a high resistance layer, rather than changing the physical structure through trench formation. This parameter-based approach achieves separation while maintaining structural simplicity.
3Ease of manufacture
If the cladding layer of the optical waveguide contacts the optical active device, then the optical coupling is simplified, but a current path is formed causing degradation in optical active device characteristics
Solution Approach 1:
The high resistance layer serves as an intermediary that blocks current flow between the optical active device and optical waveguide while allowing their adjacent placement for simplified optical coupling. The layer is positioned to interrupt the current path without disrupting optical interaction.
Solution Approach 2:
The high resistance property is applied locally at the interface where current leakage occurs, allowing the majority of the cladding layer to maintain its original properties for optimal optical coupling. This localized modification prevents harmful current paths while preserving ease of manufacture.
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 implementation effectively reduces leakage current, thereby improving the current-optical output characteristics of the optical active device by preventing unwanted current flow between the optical active device and the waveguide.
Implementation Method 1
The high resistance layer is made of a material higher in electrical resistivity than the material of the second cladding layer
Implementation Method 2
The optical waveguide portion includes a first cladding layer, an optical guiding layer, and a second cladding layer stacked on the semiconductor substrate in that order
Data Source
AI summary
An optical waveguide integrated semiconductor optical device includes a laser and an optical waveguide. The laser includes an active layer and a first cladding layer which are stacked on a second cladding layer. The optical waveguide includes an optical guiding layer and an undoped InP layer which are also stacked on the second cladding layer. A high resistance layer is located between the top surface of the optical guiding layer and a surface of the undoped InP layer and between a side of the first cladding layer and a side of the undoped InP layer.