Generation of extra facets on ridge-type triangles with (001)-, (110)-, and (201)-related equivalent slopes on GaAs (111) A substrates and stripes running in the [1¯10], [110], and [100] directions on (001) substrates during molecular beam epitaxy of GaAs/AlGaAs multilayers was investigated. By investigating local variation in layer thickness in the regions adjacent to extra (114)A, (110), and (1¯1¯1¯)B facets common to the (111)A and (001) patterned substrates and extra facets specific to the respective substrates and growth rates of the facets relative to the growth rate on the substrate plane, the orientation-dependent Ga surface diffusion length,&lgr;Ga,was elucidated as&lgr;Ga(001)≈&lgr;Ga(1¯1¯3¯)B<{&lgr;Ga(1¯1¯1 ¯)B,&lgr;Ga(3¯3¯1¯)B,&lgr;Ga(013),&lgr;Ga(113)A}<&lgr;Ga(159)≈&lgr;Ga(114)A≈&lgr;Ga(111)A<&lgr;Ga(110).That is,&lgr;Gaincreases in the order of the (001), (1¯1¯1¯)B-related, (111)A-related, and (110) surfaces.