Influence of grown-in defects on the optical and electrical properties of Si/Si1-xGex/Si heterostructures

R. Loo, M. Caymax, E. Simoen, D. Howard, M. Goryll, D. Klaes, L. Vescan, D. Gravesteijn, H. Pettersson, X. Zhang

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

The optical, electrical, and structural quality of epitaxial Si/Si1-xGex/Si layers has been studied as a function of growth temperature and layer deposition sequence. The epitaxial layers were grown by reduced pressure chemical vapor deposition in an ASM Epsilon-One reactor developed for production applications. The high material quality of both undoped and p-type modulation-doped Si/Si1-xGex/Si heterostructures which were grown without a growth interruption of more than 30 s is indicated by sharp and intense Si1-xGex photoluminescence with a FWHM of 6-10 meV for the no-phonon lines. Long growth interruptions, e.g. to change growth temperature between layer deposition, resulted in a reduced luminescence. However, this recovers after annealing the samples in a H2-plasma at 400°C for 30 min, which indicates that non-radiative recombination centers are grown-in during epitaxial growth. The electrical quality of epitaxial Si/Si1-xGex layers has been characterized by measuring the hole mobility of modulation doped samples at 4 K. Very high hole mobilities up to 8616 cm2/Vs at hole densities of 6.5 × 1011 cm-2 were measured. The hole mobility did not depend on epitaxial growth temperature down to 625°C. Further, the growth sequence and subsequent thermal treatments after the growth did not have any negative influence on the high electrical quality of the epitaxial films.

Original languageEnglish (US)
Pages (from-to)227-231
Number of pages5
JournalThin Solid Films
Volume336
Issue number1-2
DOIs
StatePublished - Dec 30 1998
Externally publishedYes

Keywords

  • 2DHG
  • Chemical vapor deposition
  • Defects
  • Heterostructures
  • Photoluminescence
  • Si

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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