Quantum Materials Corp. (fka QTMM)

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The formation of intermediate layers in covered Ge/Si heterostructures with low-temperature quantum dots: a study using high-resolution transmission electron microscopy and Raman spectroscopy

Mikhail S. Storozhevykh, Larisa V. Arapkina, Sergey M. Novikov, Oleg V. Uvarov, Vladimir A. Yuryev

(Submitted on 16 Jul 2019 (v1), last revised 17 Jul 2019 (this version, v2))

The method of software analysis of high-resolution TEM images using the peak pairs algorithm in combination with Raman spectroscopy was employed to study lattice deformations in Ge/Si(001) structures with low-temperature Ge quantum dots. It was found that the stresses do not spread in a thick Si layer above quantum dots, but completely relax via the formation of a thin boundary layer of mixed composition. However, intermixing of Ge and Si is absent beneath the Ge layer in samples with a Ge coverage of 10 Å and is completely absent in samples with a Ge coverage of 6 Å or less. This may be due to the predominance of Ge diffusion into the Si matrix from the {105} facets of Ge huts, not from the Ge wetting layer, at low temperatures of the Ge/Si structure deposition. The critical thickness of Si coverage at which the intense stress-induced diffusion takes place is determined to lie in the range from 5 to 8 nm.


https://arxiv.org/abs/1907.07169