Formation of relaxed SiGe on the buffer consists of modified SiGe stacked layers by Si pre-intermixing

P. S. Chen, S. W. Lee, M. H. Lee, C. W. Liu

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Abstract

High-quality relaxed SiGe films on Si (0 0 1) have been demonstrated with a buffer layer containing modified SiGe (m-SiGe) islands in ultra-high vacuum chemical vapor deposition (UHV/CVD) system. The m-SiGe islands are smoothened by capping an appropriate amount of Si and the subsequent annealing for 10 min. This process leads to the formation of a smooth buffer layer with non-uniform Ge content. With the m-SiGe-dot multilayer as a buffer layer, the 500-nm-thick uniform Si 0.8 Ge 0.2 layers were then grown. These m-SiGe islands can serve as effective nucleation centers for misfit dislocations to relax the SiGe overlayer. Surface roughness, strain relaxation, and crystalline quality of the relaxed SiGe overlayer were found to be a function of period's number of the m-SiGe-dot multilayer. By optimizing period number in the buffer, the relaxed Si 0.8 Ge 0.2 film on the 10-period m-SiGe-dot multilayer was demonstrated to have a threading dislocation density of 2.0 × 10 5 cm -2 and a strain relaxation of 89%.

Original languageEnglish
Pages (from-to)6076-6080
Number of pages5
JournalApplied Surface Science
Volume254
Issue number19
DOIs
Publication statusPublished - 2008 Jul 30

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Keywords

  • Relaxed SiGe
  • SiGe islands
  • Strained Si
  • UHVCVD

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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