Surface hydrogen effects on Ge surface segregation during silicon gas source molecular beam epitaxy

Using reflection-high-energy-electron diffraction (RHEED), the temperature dependence of Ge surface segregation during silicon gas source molecular beam epitaxy (Si-GSMBE) from hydride sources was studied, and it was found that surface hydrogen, which is produced by the dissociation of Si2H6 and GeH4 on the growing surface, may act as a growth-controlling surfactant. Comparison with results from solid source growth results suggests that hydrogen significantly suppresses the Ge segregation. Segregation kinetics were examined through simulation studies and the results indicate that the addition of surface hydrogen to the system inhibits segregation due to a lowering of the Gibbs heat of segregation.