Temperature-controlled coalescence during the growth of Ge crystals on deeply patterned Si substrates

Research output: Contribution to journalResearch articleContributedpeer-review


  • Roberto Bergamaschini - , University of Milan - Bicocca (Author)
  • Marco Salvalaglio - , University of Milan - Bicocca (Author)
  • Andrea Scaccabarozzi - , University of Milan - Bicocca (Author)
  • Fabio Isa - , ETH Zurich (Author)
  • Claudiu V. Falub - , ETH Zurich (Author)
  • Giovanni Isella - , Polytechnic University of Milan (Author)
  • Hans von Kaenel - , ETH Zurich (Author)
  • Francesco Montalenti - , University of Milan - Bicocca (Author)
  • Leo Miglio - , University of Milan - Bicocca (Author)


A method for growing suspended Ge films on micron -sized Si pillars in Si(001) is discussed. In [C.V. Falub et al., Science 335 (2012) 1330] vertically aligned three-dimensional Ge crystals, separated by a few tens of nanometers, were obtained by depositing several micrometers of Ge using Low-Energy Plasma-Enhanced Chemical Vapor Deposition. Here a different regime of high growth temperature is exploited in order to induce the merging of the crystals into a connected structure eventually forming a continuous, two-dimensional film. The mechanisms leading to such a behavior are discussed with the aid of an effective model of crystal growth. Both the effects of deposition and curvature-driven surface diffusion are considered to reproduce the main features of coalescence. The key enabling role of high temperature is identified with the activation of the diffusion process on a time scale competitive with the deposition rate. We demonstrate the versatility of the deposition process, which allows to switch between the formation of individual crystals and a continuous suspended film simply by tuning the growth temperature. (C) 2016 Elsevier B.V. All rights reserved.


Original languageEnglish
Pages (from-to)86-95
Number of pages10
JournalJournal of crystal growth
Publication statusPublished - 15 Apr 2016
Externally publishedYes

External IDs

Scopus 84958751681
ORCID /0000-0002-4217-0951/work/142237434



  • Growth models, Chemical vapor deposition processes, Semiconducting germanium, Semiconducting silicon, PENDEO-EPITAXIAL GROWTH, GALLIUM NITRIDE, THIN-FILMS, LAYERS, EVOLUTION, HETEROEPITAXY, INTEGRATION, MODEL