Hexagonal silicon grown from higher order silanes

Yizhen Ren, Philipp Leubner, Marcel Verheijen, Jos Haverkort, Erik Bakkers (Corresponding author)

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Abstract

We demonstrate the merits of an unexplored precursor, tetrasilane (Si4H10), as compared todisilane (Si2H6) for the growth of defect-free, epitaxial hexagonal silicon (Si). We investigate thegrowth kinetics of hexagonal Si shells epitaxially around defect-free wurtzite gallium phosphide(GaP) nanowires. Two temperature regimes are identified, representing two different surfacereaction mechanisms for both types of precursors. Growth in the low temperature regime(415 °C–600 °C) is rate limited by interaction between the Si surface and the adsorbates, and inthe high temperature regime (600 °C–735 °C) by chemisorption. The activation energy of the Sishell growth is 2.4 ± 0.2 eV for Si2H6 and 1.5 ± 0.1 eV for Si4H10 in the low temperatureregime. We observe inverse tapering of the Si shells and explain this phenomenon by a basicdiffusion model where the substrate acts as a particle sink. Most importantly, we show that, byusing Si4H10 as a precursor instead of Si2H6, non-tapered Si shells can be grown with at least 50times higher growth rate below 460 °C. The lower growth temperature may help to reduce theincorporation of impurities resulting from the growth of GaP
Original languageEnglish
Article number295602
Number of pages6
JournalNanotechnology
Volume30
Issue number29
DOIs
Publication statusPublished - 26 Apr 2019

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Keywords

  • hexagonal silicon
  • silicon epitaxy
  • higher order silanes
  • activation energy
  • core/shell nanowires

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