The Diffusion Mechanism of Ge During Oxidation of Si/SiGe Nanofins

Chappel S. Thornton, Blair Tuttle, Emily Turner, Mark E. Law, Sokrates T. Pantelides, George T. Wang, Kevin S. Jones

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

A recently discovered, enhanced Ge diffusion mechanism along the oxidizing interface of Si/SiGe nanostructures has enabled the formation of single-crystal Si nanowires and quantum dots embedded in a defect-free, single-crystal SiGe matrix. Here, we report oxidation studies of Si/SiGe nanofins aimed at gaining a better understanding of this novel diffusion mechanism. A superlattice of alternating Si/Si0.7Ge0.3layers was grown and patterned into fins. After oxidation of the fins, the rate of Ge diffusion down the Si/SiO2interface was measured through the analysis of HAADF-STEM images. The activation energy for the diffusion of Ge down the sidewall was found to be 1.1 eV, which is less than one-quarter of the activation energy previously reported for Ge diffusion in bulk Si. Through a combination of experiments and DFT calculations, we propose that the redistribution of Ge occurs by diffusion along the Si/SiO2interface followed by a reintroduction into substitutional positions in the crystalline Si.

Original languageEnglish (US)
Pages (from-to)29422-29430
Number of pages9
JournalACS Applied Materials and Interfaces
Volume14
Issue number25
DOIs
StatePublished - Jun 29 2022

All Science Journal Classification (ASJC) codes

  • General Materials Science

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