Enhancing elastic stress relaxation in SiGe/Si heterostructures by Si pillar necking

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung

Beitragende

  • F. Isa - , Swiss Federal Laboratories for Materials Science and Technology (Empa) (Autor:in)
  • M. Salvalaglio - , University of Milan - Bicocca, Technische Universität Dresden (Autor:in)
  • Y. Arroyo Rojas Dasilva - , Swiss Federal Laboratories for Materials Science and Technology (Empa) (Autor:in)
  • A. Jung - , ETH Zurich, Swiss Federal Laboratories for Materials Science and Technology (Empa) (Autor:in)
  • G. Isella - , CNR, Consiglio Nazionale delle Ricerche (CNR), Istituto di Fotonica e Nanotecnologie (IFN-CNR), IFN, L NESS Lab (Autor:in)
  • R. Erni - , Swiss Federal Laboratories for Materials Science and Technology (Empa) (Autor:in)
  • B. Timotijevic - , Centre Suisse d'Electronique et de Microtechnique (CSEM) (Autor:in)
  • P. Niedermann - , Centre Suisse d'Electronique et de Microtechnique (CSEM) (Autor:in)
  • P. Groening - , Swiss Federal Laboratories for Materials Science and Technology (Empa) (Autor:in)
  • F. Montalenti - , University of Milan - Bicocca (Autor:in)
  • H. von Kanel - , Swiss Federal Laboratories for Materials Science and Technology (Empa) (Autor:in)

Abstract

We demonstrate that the elastic stress relaxation mechanism in micrometre-sized, highly mismatched heterostructures may be enhanced by employing patterned substrates in the form of necked pillars, resulting in a significant reduction of the dislocation density. Compositionally graded Si1-xGex crystals were grown by low energy plasma enhanced chemical vapour deposition, resulting in tens of micrometres tall, three-dimensional heterostructures. The patterned Si(001) substrates consist of micrometre-sized Si pillars either with the vertical {110} or isotropically under-etched sidewalls resulting in narrow necks. The structural properties of these heterostructures were investigated by defect etching and transmission electron microscopy. We show that the dislocation density, and hence the competition between elastic and plastic stress relaxation, is highly influenced by the shape of the substrate necks and their proximity to the mismatched epitaxial material. The SiGe dislocation density increases monotonically with the crystal width but is significantly reduced by the substrate under-etching. The drop in dislocation density is interpreted as a direct effect of the enhanced compliance of the under-etched Si pillars, as confirmed by the three-dimensional finite element method simulations of the elastic energy distribution. Published by AIP Publishing.

Details

OriginalspracheEnglisch
Aufsatznummer182112
Seitenumfang5
FachzeitschriftApplied physics letters
Jahrgang109
Ausgabenummer18
PublikationsstatusVeröffentlicht - 31 Okt. 2016
Peer-Review-StatusJa
Extern publiziertJa

Externe IDs

Scopus 84994626833
ORCID /0000-0002-4217-0951/work/142237429

Schlagworte

Schlagwörter

  • THREADING DISLOCATION DENSITIES, DEFECT REDUCTION, EPITAXY, LAYERS, HETEROEPITAXY, SCATTERING, THICKNESS, FILMS, GAAS, GE