Epitaxial Ge layers on Si via GexSi1-xO2 reduction: The roles of the hydrogen partial pressure and the Ge content
The epitaxial growth of an epi-Ge layer via GexSi1-xO2 reduction in hydrogen annealing is reported. GexSi+1-x alloys with x = 0.52 and 0.82 were first grown epitaxially on Si substrates. They were then oxidized in a wet ambient and subsequently annealed in 5% or 100% H2. The reduction of Ge from its oxide state is observed in both samples with both ambients. However, an epitaxial Ge growth is only observed in the sample with x = 0.82 after the 5% H2 annealing. The other three cases result in the formation of polycrystalline Ge. The roles of the hydrogen partial pressure and the Ge content are discussed and conditions under which this novel mode of solid-phase epitaxy can occur are explained.
Key wordsEpi-Ge GeSiO2 reduction H2 annealing Si
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