Selective Epitaxial Growth of Si and Si_1-xGe_x Films by Ultrahigh-Vacuum Chemical Vapor Deposition Using Si₂H₆ and GeH₄

Abstract

Aiming at the precise profile control of Si 1- x Ge x , selective epitaxial growth (SEG) conditions and Si 1- x Ge x growth were investigated by ultrahigh-vacuum chemical vapor deposition (UHV-CVD) using Si 2 H 6 and GeH 4 . As long as the total amount of Si 2 H 6 did not exceed the critical amount, Si- and Si 1- x Ge x -SEG were both achieved independent of source gas flow rate and substrate temperature. The Ge fraction x of Si 1- x Ge x could be decided by the flow rate ratio between Si 2 H 6 and GeH 4 , independent of substrate temperature. Fast gas flow switching realized the formation of a Si(120 Å)/Si 1- x Ge x (69 Å) strained layer superlattice at 587°C.