Brittle-to-ductile transition and strain relaxation in Si$_{1-x}$Ge$_x$ linearly graded buffers

Fuente: arXiv
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Main Authors: Civiero, Riccardo, Campagna, Elena, Oliveira, Afonso Cerdeira, Zoellner, Marvin Hartwig, Impelluso, Davide, Chrastina, Daniel, Capellini, Giovanni, Isella, Giovanni
Format: Preprint
Published: 2025
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author Civiero, Riccardo
Campagna, Elena
Oliveira, Afonso Cerdeira
Zoellner, Marvin Hartwig
Impelluso, Davide
Chrastina, Daniel
Capellini, Giovanni
Isella, Giovanni
author_facet Civiero, Riccardo
Campagna, Elena
Oliveira, Afonso Cerdeira
Zoellner, Marvin Hartwig
Impelluso, Davide
Chrastina, Daniel
Capellini, Giovanni
Isella, Giovanni
contents The strain-relaxation mechanism of a set of Si$_{0.6}$Ge$_{0.4}$ linearly graded buffers (LGBs), grown following different temperature profiles, has been investigated by means of defect-etching and variable-temperature high-resolution X-ray diffraction (VT-HRXRD). Defect-etching experiments demonstrate that a sharp increase of threading dislocation density (TDD) from $3 \times 10^{5}$\,cm$^{-2}$ to $1.2 \times 10^{6}$\,cm$^{-2}$ takes place when the final growth temperature exceeds a critical value T$_c\approx 530^\circ$C. VT-HRXRD measurements show that in low TDD samples extra relaxation takes place for annealing temperatures larger than T$_c$, thanks to the nucleation of new dislocations. These results indicate that, below T$_c$, strain relaxation is driven by the gliding of existing dislocations while above T$_c$ new dislocations are nucleated, suggesting a link with our results and the brittle-to-ductile transition in Si$_{1-x}$Ge$_x$ alloys.
format Preprint
id arxiv_https___arxiv_org_abs_2512_19121
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Brittle-to-ductile transition and strain relaxation in Si$_{1-x}$Ge$_x$ linearly graded buffers
Civiero, Riccardo
Campagna, Elena
Oliveira, Afonso Cerdeira
Zoellner, Marvin Hartwig
Impelluso, Davide
Chrastina, Daniel
Capellini, Giovanni
Isella, Giovanni
Materials Science
The strain-relaxation mechanism of a set of Si$_{0.6}$Ge$_{0.4}$ linearly graded buffers (LGBs), grown following different temperature profiles, has been investigated by means of defect-etching and variable-temperature high-resolution X-ray diffraction (VT-HRXRD). Defect-etching experiments demonstrate that a sharp increase of threading dislocation density (TDD) from $3 \times 10^{5}$\,cm$^{-2}$ to $1.2 \times 10^{6}$\,cm$^{-2}$ takes place when the final growth temperature exceeds a critical value T$_c\approx 530^\circ$C. VT-HRXRD measurements show that in low TDD samples extra relaxation takes place for annealing temperatures larger than T$_c$, thanks to the nucleation of new dislocations. These results indicate that, below T$_c$, strain relaxation is driven by the gliding of existing dislocations while above T$_c$ new dislocations are nucleated, suggesting a link with our results and the brittle-to-ductile transition in Si$_{1-x}$Ge$_x$ alloys.
title Brittle-to-ductile transition and strain relaxation in Si$_{1-x}$Ge$_x$ linearly graded buffers
topic Materials Science
url https://arxiv.org/abs/2512.19121