Epitaxial Waveguide Voids for Thermal Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing processes for forming wavelength tunable laser diodes struggle to achieve a flat waveguide layer surface while maintaining thermal insulation, leading to increased optical loss and instability in the semiconductor optical device.
Innovation Solution
A process involving the formation of voids beneath the waveguide layer by selectively growing a dummy layer and etching it away using a faster etchant, which allows for the creation of a flat and smooth surface for the waveguide structure, enhancing thermal isolation and reducing optical loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If voids are formed under the waveguide layer to enhance thermal insulation, then thermal isolation is improved, but the waveguide layer surface becomes non-flat leading to increased optical loss
Solution Approach 1:
The patent divides the structure into three distinct segments: the waveguide layer, the dummy layer, and the support layer. This segmentation allows the dummy layer to be selectively removed to form voids for thermal isolation while the support layer maintains the flatness required for the waveguide layer, resolving the contradiction between thermal isolation and surface flatness.
Solution Approach 2:
The patent introduces a dummy layer as an intermediary element between the waveguide layer and the support layer. This dummy layer serves as a sacrificial material that is selectively removed to create voids, enabling thermal isolation without compromising the flatness of the waveguide layer surface, as the support layer underneath maintains the structural integrity and flatness.
2Manufacturing precision
If the waveguide layer surface is made flat to reduce optical loss, then optical performance is improved, but thermal insulation capability deteriorates
Solution Approach 1:
The patent segments the structure into distinct functional layers: the waveguide layer for optical performance, the dummy layer for thermal isolation, and the support layer for mechanical stability. This segmentation allows the support layer to maintain flatness for optical performance while the dummy layer provides thermal isolation through selectively formed voids.
Solution Approach 2:
The dummy layer acts as an intermediary that enables thermal isolation without affecting the flatness of the waveguide layer. By selectively removing portions of the dummy layer to form voids, the patent achieves thermal insulation while the overlying waveguide layer maintains its flat surface for optimal optical performance.
3Loss of energy
If a dummy layer is grown and then removed to form voids, then thermal isolation is enhanced, but the process complexity increases
Solution Approach 1:
The patent employs selective epitaxial growth where the dummy layer grows only in specific regions where voids are desired, and selective removal where the dummy layer is etched away only in certain areas. This self-service approach allows the process to automatically create the desired void pattern without requiring additional masking or patterning steps, reducing overall process complexity.
Solution Approach 2:
The patent utilizes parameter changes in the epitaxial growth process, specifically controlling growth conditions to achieve selective growth of the dummy layer. By adjusting growth parameters such as temperature, pressure, and precursor flow rates, the dummy layer is grown only in regions where voids are needed, simplifying the overall process by eliminating the need for additional patterning steps.
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 process achieves a flat and smooth waveguide surface, improving the stability and reducing optical loss, while allowing for efficient thermal isolation and precise control of the waveguide layer's temperature, enabling effective wavelength tuning.
Implementation Method 1
immersing the semiconductor substrate within an etchant so as to form a void in a region the dummy layer exists, where the etchant shows an etching rate for the dummy layer enough faster than an etching rate for the supplemental layer and the semiconductor substrate
Implementation Method 2
Powering the heater, the reflector region may change a temperature thereof
Implementation Method 3
form voids under the waveguide layer to enhance thermal insulation
Data Source
AI summary
A process of forming a semiconductor optical device is disclosed. The semiconductor optical device provides a waveguide structure accompanied with a heater for varying a temperature of the waveguide structure. The process includes steps of: (a) forming a striped mask on a semiconductor substrate; (b) selectively growing a dummy layer on the semiconductor substrate; (c) removing the patterned mask; (d) burying the dummy layer by a supplemental layer; (e) exposing a portion of the dummy layer by etching a portion of the supplemental layer; (f) and removing the dummy layer by immersing the dummy layer within a solution that shows an etching rate for the dummy layer enough faster than an etching rate for the supplemental layer and the substrate so as to leave a void in a region the dummy layer had existed.