Self-assembled Ge islands are weakly ordered along the intrinsic step direc
tion when grown directly on well-prepared biatomic-stepped vicinal Si(001)
surfaces. Prominent two-dimensional ordering of Ge islands is realized when
a SiGe/Si multilayer is predeposited on such vicinal Si(001) surfaces and
step-bunching takes place. The ordering helps to narrow the size distributi
on of the Ge islands. This provides an effective method for controlling the
Ge islands in both ordering and size. (C) 1998 Elsevier Science S.A. All r
ights reserved.