V-Groove Substrate for Lattice-Mismatched Semiconductor Dislocation Control
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Solution Overview
Problem
Current semiconductor technologies face challenges in reducing dislocation defects in lattice-mismatched semiconductor heterostructures, which limit the performance and functionality of devices such as gallium arsenide layers grown on silicon substrates, due to high defect densities and the complexity of existing defect-reduction processes.
Innovation Solution
The approach involves forming limited-area regions with upper portions substantially exhausted of threading dislocations and other defects by creating a V-groove in the semiconductor substrate, using a dislocation-blocking mask with a specific geometry and orientation to trap dislocations, and employing selective epitaxial growth to minimize defect formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If heteroepitaxial growth is used to fabricate lattice-mismatched semiconductor structures, then functionality and performance are improved, but dislocation defect density increases
Solution Approach 1:
The substrate surface is segmented into multiple regions with different crystal orientations by etching V-grooves, creating distinct growth zones that control dislocation propagation paths and reduce overall defect density in the heteroepitaxial structure
Solution Approach 2:
Different regions of the substrate are given different local crystal orientations through selective V-groove etching, allowing each region to serve a specific function in controlling dislocation behavior while maintaining overall structure integrity
2Reliability
If V-groove formation with specific geometry is implemented, then dislocation termination is improved, but device complexity increases
Solution Approach 1:
V-grooves are formed with asymmetric geometry where the groove angle and depth are specifically designed to match the crystallographic directions of the substrate, creating preferential paths for dislocation termination while maintaining manufacturability
Solution Approach 2:
V-grooves are pre-formed in the substrate before heteroepitaxial growth to establish dislocation termination paths in advance, allowing subsequent material growth to naturally follow the predetermined defect-free zones
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 method enables the fabrication of semiconductor devices with reduced dislocation defects, allowing for the integration of lattice-mismatched materials with improved performance and functionality, such as gallium arsenide on silicon substrates, by effectively terminating dislocations at the substrate surface, thereby enhancing device reliability and efficiency.
Implementation Method 1
A recess, with a maximum depth d and a recessed surface comprising a second crystal orientation, is defined in the exposed portion of the substrate. A second crystalline semiconductor material having a lattice mismatch with the first crystalline semiconductor material is formed in the recess. The lattice mismatch creates defects in the second crystalline semiconductor material, and the defects terminate at a distance H above a deepest point of the recess.
Implementation Method 2
Hetero-integration of dissimilar semiconductor materials, for example, III-V materials, such as gallium arsenide, gallium nitride, indium aluminum arsenide, and/or germanium with silicon or silicon-germanium substrate, is an attractive path to increasing the functionality and performance of the CMOS platform. In particular, heteroepitaxial growth can be used to fabricate many modern semiconductor devices
Data Source
AI summary
A method of forming a semiconductor structure includes forming an opening in a dielectric layer, forming a recess in an exposed part of a substrate, and forming a lattice-mismatched crystalline semiconductor material in the recess and opening.