Strained Material Islands Buckling Prevention via Segmentation
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Solution Overview
Problem
Existing methods for forming bulk structures of III-V materials, such as InGaN, face challenges like buckling and delamination due to high strain, which are exacerbated by the number of steps required and lattice mismatch issues, leading to inefficiencies in semiconductor manufacturing.
Innovation Solution
A method involving the formation of islands of strained material on a first substrate, bonding to a target substrate, and partial relaxation through a heat treatment, with the presence of both substrates reducing buckling and allowing for simultaneous relaxation and detachment in a single step, using a relaxing material like BPSG with a glass transition temperature between 600-1000°C, and optional ion implantation for weakening the seed layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a relaxation step is performed by heating the structure and flowing the compliant layer, then the strained material can be partially relaxed, but buckling occurs causing the relaxed layer to have an undulated shape
Solution Approach 1:
The patent divides the continuous strained layer into discrete islands of strained material separated by trenches. This segmentation allows each island to relax independently without causing buckling of the entire layer, as the trenches provide stress release paths and prevent the propagation of buckling waves across the structure.
Solution Approach 2:
The patent extracts the compliant layer from the final structure by detaching it from the substrate after relaxation. This removal eliminates the source of buckling (the flowing compliant layer) while retaining the relaxation benefits, as the strained material islands have already undergone partial relaxation during the heating step.
2Reliability
If multiple processing steps are used to achieve relaxation and transfer, then the strained material can be relaxed and transferred to target substrate, but the process becomes complex with many steps
Solution Approach 1:
The patent combines multiple functions into a single processing step: the heating step simultaneously performs relaxation of the strained material islands and detachment of the compliant layer. This merging of relaxation and detachment operations reduces the total number of steps while maintaining the quality of the relaxed material.
Solution Approach 2:
The patent performs preliminary relaxation of the strained material islands during the heating step before final transfer to the target substrate. This preliminary action ensures that the material is already partially relaxed when transferred, improving the quality of the final structure and reducing the need for subsequent relaxation steps.
3Manufacturing precision
If the strain of the strained material is high, then the lattice parameter can be controlled, but cracking and delamination occur
Solution Approach 1:
The patent segments the highly strained layer into islands separated by trenches, which prevents the propagation of cracks and delamination across the entire structure. The trenches act as stress release paths that accommodate the high strain without causing catastrophic failure, allowing lattice parameter control to be maintained while preserving structural integrity.
Solution Approach 2:
The patent introduces trenches as an intermediary structure between the strained material islands and the substrate. These trenches serve as stress buffers that mediate the high strain by providing localized relaxation zones, preventing the transmission of damaging stresses to the overall structure while maintaining the desired lattice parameters in the islands.
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 the number of steps, minimizes buckling, and prevents delamination by promoting lateral relaxation without causing crystal defects, enabling the production of high-quality, at least partially relaxed strained material with controlled lattice parameters.
Implementation Method 1
the presence of both substrates reducing buckling
Implementation Method 2
using a relaxing material like BPSG with a glass transition temperature between 600-1000°C
Implementation Method 3
at least partially relaxing the islands of the strained material by a first heat treatment
Implementation Method 4
optional ion implantation for weakening the seed layer
Data Source
AI summary
The present invention relates to the field of semiconductor manufacturing. More specifically, it relates to a method of forming islands of at least partially relaxed strained material on a target substrate including the steps of forming islands of the strained material over a side of a first substrate; bonding the first substrate, on the side including the islands of the strained material, to the target substrate; and after the step of bonding splitting the first substrate from the target substrate and at least partially relaxing the islands of the strained material by a first heat treatment.