Pattern level assembly of Ge quantum dots on Si with focused ion beam templating

Abstract

Array level assembly mechanisms are described for controlled nucleation of Ge quantum dots (QDs) on Si(100) surfaces templated by low dose focused ion beam pulses. The registration rates of QD positions with the target sites approach 100% for site separations of 100nm and above, but incomplete occupancy is observed at closer distances. We investigate the dependence of the QD array perfection on the site separation, and identify the competition between the intended nucleation sites for the supply of Ge adatoms as a key factor limiting the large area registration fidelity.