As4 pressure dependence of surface segregation of indium atoms during molecular beam epitaxy of In0.08Ga0.92As/GaAs superlattices on (411)A GaAs substrates

AS(4) pressure dependence of surface segregation of In atoms during molecular beam epitaxy (MBE) growth of pseudomorphic In0.08Ga0.92As/GaAs (7.5 nm/11.2 nm) superlattices (SLs) on (411)A GaAs substrates was investigated by high resolution x-ray diffraction (HRXRD) and 12 K photoluminescence measurements. Surface segregation lengths of In atoms (lambda: Ile decay length of In content profile along the growth direction) determined by HRXRD decrease with increasing V/III ratio for both the (411)A and simultaneously grown (100) SLs. lambda for the (411)il SL grown under V/III (As-4/Ca) pressure ratio of 10 was 2.32 nm, which is 1.4 times larger than that for the (100) SL, while lambda was almost the same for both the (411)A and (100) SLs grown under V/III=30. With decreasing V/III ratio, In surface segregation increased, and InGaAs/GaAs interface flatness was improved in the (411)A InGaAs/GaAs SLs. Reduced As-4 pressure results in enhanced surface segregation of In atoms as well as enhanced surface migration of In atoms during MBE growth of the (411)A InGaAs/ClaAs SLs. (C) 2000 American Vacuum Society.