The 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 [¯110], [110] and [100] directions on (001) substrates, was investigated during the molecular beam epitaxy of GaAs/AlGaAs multi-layers. By investigating local variations in the layer thickness in regions adjacent to extra (114)A, (110) and (¯1¯1¯1)B facets which were common to the (111)A and (001) patterned substrates, and extra facets which were related 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 lengths were determined. They increased in the order: (001), (¯1¯1¯1)B-related, (111)A-related and (110). Or, diagrammatically,

 (001) <(¯1¯1¯1)B < (159) < (110)

 (¯1¯1¯3)B  (¯3¯3¯1)B  (114)A  

   (013)B  (111)A  

   (113)B    

T.Takebe, M.Fujii, T.Yamamoto, K.Fujita, T.Watanabe: Journal of Applied Physics, 1997, 81[11], 7273-8