Optimization of Si-C reaction temperature and Ge thickness in C-mediated Ge dot formation

Yuhki Satoh, Yuhki Itoh, Tomoyuki Kawashima, Katsuyoshi Washio

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

To form Ge dots on a Si substrate, the effect of thermal reaction temperature of sub-monolayer C with Si (100) was investigated and the deposited Ge thickness was optimized. The samples were prepared by solid-source molecular beam epitaxy with an electron-beam gun for C sublimation and a Knudsen cell for Ge evaporation. C of 0.25 ML was deposited on Si (100) at a substrate temperature of 200 °C, followed by a high-temperature treatment at the reaction temperature (TR) of 650-1000 °C to create Si-C bonds. Ge equivalent to 2 to 5 nm thick was subsequently deposited at 550 °C. Small and dense dots were obtained for TR = 750 °C but the dot density decreased and the dot diameter varied widely in the case of lower and higher TR. A dot density of about 2 × 1010 cm-2 was achieved for Ge deposition equivalent to 3 to 5 nm thick and a standard deviation of dot diameter was the lowest of 10 nm for 5 nm thick Ge. These results mean that C-mediated Ge dot formation was strongly influenced not only by the c(4 x 4) reconstruction condition through the Si-C reaction but also the relationship between the Ge deposition thickness and the exposed Si (100)-(2 x 1) surface area.

Original languageEnglish
Pages (from-to)29-31
Number of pages3
JournalThin Solid Films
Volume602
DOIs
Publication statusPublished - 2016 Mar 1

Keywords

  • Carbon
  • Germanium
  • Germanium Dots
  • Mediated Growth
  • Molecular Beam Epitaxy
  • Silicon

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

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