Insights into the Origins of Guided Microtrenches and Microholes/rings from Sn Segregation in Germanium–Tin Epilayers

Wu, Shaoteng; Lin, Zhenyang; Son, Bongkwon; Chen, Qimiao; Zhou, Hao; Tan, Chuan Seng

doi:10.1021/acs.jpcc.0c03820

Cited by 9 publications

(7 citation statements)

References 40 publications

(104 reference statements)

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“…The mechanism for the so-called “pipe diffusion” of Sn atoms was recently proposed in ref , where it was argued that Sn transport is facilitated by the propagation of dislocations toward the surface, such as by threading arms of MDs. Moreover, the Sn transport toward the surface may lead to the accumulation of liquid Sn precipitates, which are known to play a major role in phase separation at temperatures above the eutectic temperature of GeSn (231 °C). , In these studies, the phase-separation process is believed to involve the free movement of Sn droplets on the sample surface that aid to decompose the GeSn layer with the subsequent redeposition of equilibrium-composition Ge 0.99 Sn 0.01 . As a result, the sample surface is characterized by excavated trenches and segregation spots, which are similar to the spotted surface of sample S2 after annealing for 4 h (Figure b).…”

Section: Discussionmentioning

confidence: 99%

Quantitative Correlation Study of Dislocation Generation, Strain Relief, and Sn Outdiffusion in Thermally Annealed GeSn Epilayers

Stanchu

Kuchuk

Mazur

et al. 2021

Crystal Growth & Design

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The instability during the growth and processing of epitaxial GeSn layers with high Sn molar fraction and high compressive strain is still to be fully studied. In this work, the relationship among strain relief, dislocations, and Sn outdiffusion in GeSn layers with a Sn content of ∼9 atom % was studied as a function of pre-existing misfit/threading dislocation (MD/TD) density and annealing time at 300 °C. For a GeSn epilayer strained to a Ge-on-Si virtual substrate (Ge-VS), an increase of strain relief by a factor of ∼2 is observed after 2 h of annealing, without a significant effect on strain relaxation for a more prolonged temperature treatment. This is explained by the limited propagation or elongation of pre-existing MDs at the interface of GeSn/Ge-VS. The onset of Sn outdiffusion and the appearance of segregation spots are observed for the GeSn epilayers with significant strain relaxation (≥50%) before annealing, for which the density of MDs ≥ 2 × 10 5 cm −1 . This is explained by generation of high-density MDs/TDs acting as preferential sites for Sn accumulation during the growth of the GeSn layer. This work explicitly provides an understanding that dislocation engineering is one of the key factors for the stability and performance of GeSn semiconductors.

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Section: Discussionmentioning

confidence: 99%

Quantitative Correlation Study of Dislocation Generation, Strain Relief, and Sn Outdiffusion in Thermally Annealed GeSn Epilayers

Stanchu

Kuchuk

Mazur

et al. 2021

Crystal Growth & Design

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“…2, Due to the incorporation of Sn atoms, the GeSn epilayer is less stable than the Ge layer. 20 The etched micro-holes from reactions 1 and 2 can be observed at the critical temperature of ~ 625 °C, different from the Ge layer of ~700 °C. 3, the Ni particles act as the catalyst to enhance the decomposing of GeSn.…”

Section: Resultsmentioning

confidence: 98%

Unusually-high growth rate (∼2.8 μm/s) of germania nanowires and its hierarchical structures by an in-situ continuous precursor supply

Chen

Zhang

et al. 2023

Ceramics International

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“…Segregation and migration of Sn droplets lead to the morphological evolution and formation of microscale patterns with stripes and wires during growth and/or further thermal treatments of metastable GeSn films with >8% Sn content at relatively low temperatures. 28 Depending on the growth conditions, various structures originate from reducing the Gibbs free energy during the migration of droplets at the surface of strained and Sn-supersaturated alloys such as tin wires, 29 trenches and ridges, 30 and high crystalline quality stripes of low Sn content. 31 In the presented studies, the strained Ge 1−x Sn x alloys with x = 10.5% were cooled in a vacuum chamber after the CVD growth from 300 °C down to room temperature.…”

Section: Morphology Of Strained Epitaxial Gesn Alloysmentioning

confidence: 99%

Conductivity-Type Conversion in Self-Assembled GeSn Stripes on Ge/Si(100) under Electric Field

Кондратенко

Lytvyn

Kuchuk

et al. 2021

ACS Appl. Electron. Mater.

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We report on the electronic properties of self-assembled Ge 99 Sn 1 stripes surrounded by inhomogeneous Ge 96.6 Sn 3.4 area resulting from the segregation and migration of Sn droplets on Ge 89.5 Sn 10.5 /Ge/Si(100). The sample with microscale patterns was characterized at the nanoscale by a combination of techniques including X-ray diffraction, Raman spectroscopy, and scanning probe microscopy. Kelvin probe force microscopy (KPFM) nanoscale maps of the local work function show a spatial inhomogeneity up to 200 meV, which is explained by the band bending induced by holes trapped at the surface states of the Sn droplets. The scanning capacitance microscopy (SCM) of the local charge carrier density shows the dominant p-type conductivity with lateral variation in the hole-density by 1 order of magnitude. The microscale patterns are depleted by holes, and we experimentally revealed an electric-field-induced conductivity-type conversion from p to n in a self-assembled GeSn stripe. Finally, we presented a model and calculations that support the described above experimentally observed phenomena. This work explicitly provides an understanding of the electronic properties of the GeSn micrometer-scale stripes that is important for the implementation of the GeSn in photonic, optoelectronic, electronic, and energy storage devices.

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Insights into the Origins of Guided Microtrenches and Microholes/rings from Sn Segregation in Germanium–Tin Epilayers

Abstract: Insights into the origins of guided microtrenches and microholes/rings from Sn segregation in germanium-tin epilayers

Cited by 9 publications

References 40 publications

Quantitative Correlation Study of Dislocation Generation, Strain Relief, and Sn Outdiffusion in Thermally Annealed GeSn Epilayers

Quantitative Correlation Study of Dislocation Generation, Strain Relief, and Sn Outdiffusion in Thermally Annealed GeSn Epilayers

Unusually-high growth rate (∼2.8 μm/s) of germania nanowires and its hierarchical structures by an in-situ continuous precursor supply

Conductivity-Type Conversion in Self-Assembled GeSn Stripes on Ge/Si(100) under Electric Field

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