As-4 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 molecul ar beam epitaxy (MBE) growth of pseudomorphic In0.08Ga0.92As/GaAs (7.5 nm/1 1.2 nm) superlattices (SLs) on (411)A GaAs substrates was investigated by h igh resolution x-ray diffraction (HRXRD) and 12 K photoluminescence measure ments. Surface segregation lengths of In atoms (lambda: Ile decay length of In content profile along the growth direction) determined by HRXRD decreas e 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 r atio of 10 was 2.32 nm, which is 1.4 times larger than that for the (100) S L, 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 increa sed, and InGaAs/GaAs interface flatness was improved in the (411)A InGaAs/G aAs SLs. Reduced As-4 pressure results in enhanced surface segregation of I n 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.