IN-SITU OBSERVATIONS OF GAAS INITIAL GROWTH ON SI SUBSTRATES STUDIED USING AN ULTRAHIGH-VACUUM TRANSMISSION-ELECTRON MICROSCOPE MOLECULAR-BEAM EPITAXY SYSTEM

An ultrahigh vacuum transmission-electron microscope equipped with a m olecular-beam epitaxy chamber (UHV-TEM/MBE) has been constructed in or der to observe the in situ heteroepitaxial growth stages of GaAs/Si. P reliminary in situ TEM observations of the initial growth stages of si ngle-crystalline GaAs on vicinal (100) Si (thickness, 20-50 Angstrom) were carried out using this UHV-TEM/MBE system under optimized growth conditions. The assignment of dislocations, stacking faults and/or twi ns, and the relation with the critical-size of islands were examined b ased on moire images in individual islands (size, 40-1000 Angstrom) fo r the first time.