Layered InP-on-Silicon Structure for Thermal Strain Compensation
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Solution Overview
Problem
Combining InP-based devices with silicon substrates in semiconductor technology faces challenges due to compressive strain induced by thermal mismatch, leading to undulations and degraded material quality, particularly in thicker III-V stacks.
Innovation Solution
Incorporating an InXP layer with a small amount of Al or Ga into the InP-based layer on a silica-coated silicon substrate to introduce tensile strain, compensating for the compressive strain and improving substrate properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an InP-based layer is grown on a silicon substrate, then integration of InP-based devices on silicon platform is enabled, but compressive strain induced by thermal mismatch causes undulations and degraded material quality
Solution Approach 1:
A silica layer is introduced as an intermediary between the silicon substrate and the InP-based layer. This intermediate layer acts as a buffer that reduces the thermal mismatch and mechanical stress between the silicon substrate and the InP-based layer, thereby preventing undulations and material degradation while maintaining integration capability
Solution Approach 2:
The structure employs a composite layered architecture consisting of silicon substrate, silica layer, InP-based layer, and InXP layer. This composite structure combines materials with different thermal expansion coefficients in a controlled manner, where each layer contributes specific properties to mitigate the thermal mismatch problem while enabling device integration
2Reliability
If the III-V stack thickness is increased, then device functionality is improved, but compressive strain causes undulations and degraded material quality
Solution Approach 1:
An InXP layer with tensile strain is deposited on the InP-based layer before completing the III-V stack. This preliminary application of tensile strain counteracts the compressive strain that would otherwise accumulate with increased stack thickness, preventing undulations and maintaining material quality throughout the fabrication process
3Ease of manufacture
If thermal mismatch between silicon substrate and InP-based layer is not compensated, then fabrication process is simplified, but compressive strain degrades material quality
Solution Approach 1:
The silica layer serves as a simple intermediary that can be deposited using standard fabrication processes, providing thermal mismatch compensation without significantly complicating the manufacturing workflow. The layer acts as a passive buffer that reduces stress while maintaining process compatibility
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 InXP layer mitigates compressive thermal strain, enhancing the quality of III-V devices and semiconductor stacks, especially in thicker layers, by maintaining material integrity and improving electronic and optoelectronic properties.
Implementation Method 1
Incorporating an InXP layer with a small amount of Al or Ga into the InP-based layer on a silica-coated silicon substrate to introduce tensile strain, compensating for the compressive strain and improving substrate properties
Data Source
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AI summary
There is provided a layered semiconductor structure 100 and a method of fabricating a layered semiconductor structure. The layered semiconductor structure comprises a silicon substrate (101), a silica layer on the silicon substrate (102), an InP-based layer on the silica layer (103), and an InXP layer (104) on the InP-based layer, wherein X is one of Al or Ga, or a combination of Al and Ga.