Impact of template variations on shape and arrangement of Si/Ge quantum dot arrays

Templated self-assembly allows the fabrication of quantum dot (QD) arrays for use in nanoelectronic devices. Here, we show the strong dependence of the shape and arrangement of QDs on the template structures. Arrays of etched pits are patterned on Si (100) substrates by extreme ultraviolet interference lithography on which Si/Ge layers are grown in a molecular beam epitaxy system. Single Ge dome clusters or quantum molecules consisting of four Ge hut clusters are obtained by a change of the pit diameter. Both arrays exhibit a narrow size distribution and exact alignment of the dots. In addition, multiple stacking of these arrays is demonstrated. (C) 2008 American Institute of Physics.