The position of Ge islands formed on Si substrates by self-assembly can be
determined by adjacent lithographically defined features. Islands tend to f
orm near the edges of narrow Si lines defined by oxide isolation and conven
tional selective Si epitaxial deposition, offering the possibility of formi
ng small device features without fine lithography. Multiple rows of islands
can form on wider lines. The alignment is probably caused by easier nuclea
tion on shallow facets; therefore, the position of the Ge islands can be in
fluenced by controlling the shape of the underlying Si surface.