III-V Thin Film Growth on SOI With Defect-Confined Lateral Trenches
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Solution Overview
Problem
Current methods for growing III-V compound semiconductors on silicon-on-insulators face challenges such as crystalline defects and dislocation issues, which hinder the integration of high-quality III-V materials with Si-based optoelectronic devices, particularly in achieving bufferless and dislocation-free structures on larger scales suitable for practical applications like Si photonics.
Innovation Solution
A method involving a layered substrate with patterned mask layers and anisotropic wet etching to form lateral trenches with {111}-oriented Si seed surfaces, allowing for selective lateral growth of epitaxial III-V compound semiconductors using MOCVD, resulting in non-defective portions on the buried oxide layer while confining defects, enabling dislocation-free III-V nano/micro structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If blanket epitaxial growth of III-V materials on Si wafers is used, then large-area coverage is achieved, but crystalline defects and dislocations propagate through the entire structure
Solution Approach 1:
The patent segments the growth area by using patterned masks to define specific regions where III-V materials are grown only in certain areas (e.g., around contact holes or in inter-router spaces) rather than blanket coverage. This segmentation allows large-area substrates to be processed while maintaining high crystalline quality in the specific grown regions by confining defects to mask edges and non-growth areas.
2Manufacturing precision
If thick buffer layers are used to reduce dislocation density, then crystalline quality improves, but device interconnection becomes difficult
Solution Approach 1:
The patent extracts or removes the need for thick buffer layers by using thin-film epitaxial growth combined with defect filtering techniques. The patterned growth approach allows defects to be confined to specific regions (mask edges, trench walls) while the device regions maintain high crystalline quality without requiring thick buffering, thus enabling direct device interconnection.
Solution Approach 2:
The patent introduces patterned masks and trench structures as intermediary elements that act as defect filters. These intermediaries capture and confine crystalline defects at their interfaces while allowing the III-V material to grow with high quality in the desired device regions, eliminating the need for thick buffer layers.
3Manufacturing precision
If selective area growth is used to produce dislocation-free structures, then crystalline quality improves, but nano-scale dimensions limit practical applications
Solution Approach 1:
The patent transitions from two-dimensional planar growth to three-dimensional vertical growth within patterned trenches and around contact holes. This dimensional change allows the formation of high-aspect-ratio structures with excellent crystalline quality that can serve as effective defect filters while providing sufficient volume for practical optoelectronic device applications.
4Ease of manufacture
If conventional epitaxial growth on bulk Si is used, then manufacturing simplicity is maintained, but integration with Si-based optoelectronic devices is limited
Solution Approach 1:
The patent applies local quality by using patterned masks to create spatially varying growth conditions on the Si substrate. Different regions have different properties: some areas have III-V material grown with specific orientations and thicknesses, while other areas remain as bare Si or have different mask configurations. This enables simultaneous optimization for both manufacturing simplicity (using standard Si substrates) and integration capability (with patterned III-V regions for optoelectronic devices).
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 enables the growth of high-quality, dislocation-free III-V alloys on SOI platforms, facilitating direct integration with Si-based optoelectronic devices and providing strong mode confinement, suitable for various dimensions and chemical compositions, enhancing the performance and integration of III-V materials in Si photonics.
Implementation Method 1
etching each lateral Si surface of each lateral trench by anisotropic wet etching thereby forming one or more {111}-oriented Si seed surfaces
Implementation Method 2
growing an epitaxial layer of the III-V compound semiconductor laterally within its respective lateral trench by metal organic chemical vapor deposition
Implementation Method 3
growing an epitaxial layer of the III-V compound semiconductor laterally within its respective lateral trench by metal organic chemical vapor deposition thereby forming one or more epitaxial layers between the buried oxide layer and the patterned mask layer
Data Source
AI summary
The present disclosure relates to a method for growing III-V compound semiconductors on silicon-on-insulators. Starting from {111}-oriented Si seed surfaces between a buried oxide layer and a patterned mask layer, the III-V compound semiconductor is grown within lateral trenches by metal organic chemical vapor deposition such that the non-defective portion of the III-V compound semiconductor formed on the buried oxide layer is substantially free of crystalline defects and has high crystalline quality.