Atmospheric pressure chemical vapor deposition techniques have been used to grow electronic quality Si-Ge epilayers on Si substrates. The degree of tetragonal strain in the layers has been determined using Raman spectroscopy. The relative energy shift of the Si-Si phonon line associated with the Si 1-xGex epilayers from a pseudoalloy of the same composition was used as a quantitative measure of the strain. Layer growth was found to be almost commensurate with the Si substrates for thicknesses in the region of ∼100 nm. For x≅0.1 the resulting films were highly strained and homogeneous. The strain diminished with increasing thickness and it was estimated that a layer would be fully relaxed when the thickness exceeded 3000 nm. The phonon linewidths provided information on the epilayer and interface quality.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)