Growth of strained Si on high-quality relaxed Si1-x Gex with an intermediate Si1-y Cy layer

S. W. Lee, Y. L. Chueh, L. J. Chen, L. J. Chou, P. S. Chen, M. H. Lee, M. J. Tsai, C. W. Liu

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Abstract

An intermediate Si1-y Cy layer in the Si1-x Gex film, replacing the conventionally graded buffer layer, was used to form the high-quality relaxed SiGe substrate. With the 700 nm thick Si0.8 Ge0.2 overlayer, such a Si1-x Gex Si1-y Cy Si1-x Gex (x=0.2, y-0.014) heterostructure has a threading dislocation density of 5.5× 105 cm-2 and a residual strain of only 2%. The surface roughness was measured to be about 4.2 nm. The long-range misfit dislocation array was formed mainly at the interface of top Si1-x Gex and Si1-y Cy. Strained-Si n -channel metal-oxide-semiconductor transistors with various buffer layers were fabricated and examined. Effective electron mobility for the strained-Si device with this substrate technology was found to be 95% higher than that of Si control device. The scheme for the formation of the relaxed Si1-x Gex film serving as a virtual substrate shall be applicable to high-speed strained-Si devices.

Original languageEnglish
Pages (from-to)1141-1145
Number of pages5
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume23
Issue number4
DOIs
Publication statusPublished - 2005 Jul 1

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ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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