Strain-Driven Dewetting and Interdiffusion in SiGe Thin Films on SOI for CMOS-Compatible Nanostructures

Strain-Driven Dewetting and Interdiffusion in SiGe Thin Films on SOI for CMOS-Compatible Nanostructures

This study provides new insight into the mechanisms governing solid state dewetting (SSD) in SiGe alloys and underscores the potential of this bottom-up technique for fabricating self-organized defect-free nanostructures for CMOS-compatible photonic and nanoimprint applications. In particular, we in...

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Bibliographic Details
Main Authors: Sonia Freddi, Michele Gherardi, Andrea Chiappini, Adam Arette-Hourquet, Isabelle Berbezier, Alexey Fedorov, Daniel Chrastina, Monica Bollani
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Nanomaterials
Subjects:
solid state dewetting
silicon germanium
nanoisland
nanostructures
strain relaxation
Mie resonators
Online Access:https://www.mdpi.com/2079-4991/15/13/965
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Summary:This study provides new insight into the mechanisms governing solid state dewetting (SSD) in SiGe alloys and underscores the potential of this bottom-up technique for fabricating self-organized defect-free nanostructures for CMOS-compatible photonic and nanoimprint applications. In particular, we investigate the SSD of Si<sub>1−x</sub>Ge<sub>x</sub> thin films grown by molecular beam epitaxy on silicon-on-insulator (SOI) substrates, focusing on and clarifying the interplay of dewetting dynamics, strain elastic relaxation, and SiGe/SOI interdiffusion. Samples were annealed at 820 °C, and their morphological and compositional evolution was tracked using atomic force microscopy (AFM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Raman spectroscopy, considering different annealing time steps. A sequential process typical of the SiGe alloy has been identified, involving void nucleation, short finger formation, and ruptures of the fingers to form nanoislands. XRD and Raman data reveal strain relaxation and significant Si-Ge interdiffusion over time, with the Ge content decreasing from 29% to 20% due to mixing with the underlying SOI layer. EDX mapping confirms a Ge concentration gradient within the islands, with higher Ge content near the top.
ISSN:2079-4991

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