Silicon Photonic Components Fabricated Using Bulk Substrate
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Solution Overview
Problem
Current photonics chip structures relying on silicon-on-insulator wafers are costly and inefficient due to the need for a thick buried oxide layer, which can be replaced by a cheaper bulk wafer substrate with improved integration of waveguide cores and electronic components.
Innovation Solution
A semiconductor substrate with trenches and pillars is used, where a dielectric layer is formed within the trenches and waveguide cores are epitaxially grown on the pillars, replacing the buried oxide layer and enabling cheaper bulk wafer usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick buried oxide layer is used in silicon-on-insulator wafers to provide bottom cladding for optical components, then the structural integrity and optical performance are improved, but the manufacturing cost and material usage increase significantly
Solution Approach 1:
The patent extracts and removes the expensive thick buried oxide layer from the silicon-on-insulator wafer structure, replacing it with a combination of semiconductor substrate and deposited dielectric layers. This extraction eliminates the primary source of high manufacturing cost while maintaining the necessary cladding function through alternative structural arrangements.
Solution Approach 2:
The patent changes the parameter of oxide layer thickness from thick (in conventional silicon-on-insulator) to thin or localized regions, and replaces bulk oxide with deposited dielectric materials. This parameter change significantly reduces material usage and cost while achieving the same functional outcome through controlled deposition processes.
2Reliability
If a thick buried oxide layer is used to provide bottom cladding, then the optical component performance is maintained, but the layout area and integration efficiency are reduced
Solution Approach 1:
The patent transitions from a vertical thick oxide layer structure to a more distributed arrangement where cladding functionality is achieved through lateral extensions and alternative layer configurations. This dimensional reorganization reduces the vertical space requirement and improves layout efficiency while maintaining optical performance.
3Reliability
If silicon-on-insulator wafers with thick buried oxide are used, then bottom cladding for optical components is provided, but the integration of electronic and optical components is less efficient
Solution Approach 1:
The patent merges the electronic and optical component fabrication processes by using the same semiconductor substrate for both types of devices. The removal of the thick buried oxide layer allows for better integration where electronic transistors and optical waveguides can be fabricated in a unified process flow, reducing manufacturing complexity and improving integration efficiency.
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 reduces manufacturing costs and improves integration by using a cheaper bulk wafer substrate while maintaining effective waveguide core performance, enhancing the layout area and operational efficiency of photonics chips.
Implementation Method 1
forming a dielectric layer having a first portion in the first trench and a second portion in the second trench
Implementation Method 2
forming a first waveguide core that is coupled to the pillar at a top surface of the substrate
Data Source
AI summary
Structures including a photodetector and methods of fabricating such structures. A substrate, which is composed of a semiconductor material, includes a first trench, a second trench, and a pillar of the semiconductor material that is laterally positioned between the first trench and the second trench. A first portion of a dielectric layer is located in the first trench and a second portion of the dielectric layer is located in the second trench. A waveguide core is coupled to the pillar at a top surface of the substrate.