Strain conservation in implantation -doped GeSi layers on Si(100)

  • Im, S. (Department of Metallurgical Engineering Yonsei University) ;
  • Nicolet, M.A. (Department of Applied Physics California Institute of Technology)
  • Published : 1997.10.01

Abstract

Metastable pseudomorphic GeSi layers grown by vapor phase epitaxy on Si(100) substrates were implanted at room temperature. The implantations were performed with 90 KeV As ions to a dose of $1\times 10^{13}\;\textrm{cm}^2$ for $Ge_{0.08}Si_{0.92}$ layers and 709 keV $BF_2^+$ ions to a dose of $3\times 10^{13}\;\textrm{cm}^2$ for $Ge_{0.06}Si_{0.94}$layers. The samples were subsequently annealed for short 10-40 s durations in a lamp furnace with a nitrogen ambient or for a long 30 min period in a vacuum tube furnace. For $Ge_{0.08}Si_{0.92}$samples annealed for a 30 min-longt duration at $700^{\circ}C$ the dopant activation can only reach 50% without introducing significant strain relaxaion whereas samples annealed for short 40s periods (at $850^{\circ}C$) can achieve more than 90% activation without a loss of strain, For $Ge_{0.06}Si_{0.94}$samples annealed for either 40s or 30min at $800^{\circ}C$ full electrical activation of the boron is exhibited in the GeSi epilayer without losing their strain. However when annealed at $900^{\circ}C$ the strain in both implanted and unimplanted layers is partly relaxed after 30min whereas it is not visibly relaxed after 40s.

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