Epitaxial Si 1− x Ge x grown into fine contact hole by ultrahigh-vacuum chemical vapor deposition

Abstract

An ultrahigh-vacuum chemical vapor deposition technique with disilane (Si 2H 6) and germane (GeH 4) molecular flux is applied to Si 1− x Ge x ( x=0–0.15) selective growth into fine contact holes. The growth behavior of epitaxial Si 1− x Ge x layer is influenced by addition of GeH 4 with Si 2H 6 flow rate kept at constant, which is interpreted by estimation of facet growth rates. The growth rates of (311) and (111) facets are drastically decreased by addition of a small amount of GeH 4. As a result, in the fine holes, the epitaxial layer height of Si 1− x Ge x is limited by the (311) growth rate and decreased compared with pure Si.