SURFACE HYDROGEN EFFECTS ON GE SURFACE SEGREGATION DURING SILICON GAS-SOURCE MOLECULAR-BEAM EPITAXY

Using reflection-high-energy-electron diffraction (RHEED), the tempera ture dependence of Ge surface segregation during silicon gas source mo lecular beam epitaxy (Si-GSMBE) from hydride sources was studied, and it was found that surface hydrogen, which is produced by the dissociat ion Of Si2H6 and GeH4 on the growing surface, may act as a growth-cont rolling surfactant. Comparison with results from solid source growth r esults suggests that hydrogen significantly suppresses the Ge segregat ion. Segregation kinetics were examined through simulation studies and the results indicate that the addition of surface hydrogen to the sys tem inhibits segregation due to a lowering of the Gibbs heat of segreg ation.