| AVS 56th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology | Tuesday Sessions |
| Session NS2-TuA |
| Session: | Templated Self-Assembly |
| Presenter: | J.F. Graham, University of Virginia |
| Authors: | J.F. Graham, University of Virginia C.D. Kell, University of Virginia J.A. Floro, University of Virginia R. Hull, Rensselaer Polytechnic Institute |
| Correspondent: | Click to Email |
An important application of the focused ion beam (FIB) is nanoscale modification of surfaces for directed self-assembly of nanostructures. In previous work, we have demonstrated Ga+ FIB patterning of Si(100) substrates followed by epitaxial deposition, resulting in templated nucleation of Ge quantum dots (QDs) and SiGe quantum dot molecules (QDMs). Such positional control of QD growth using FIBs should be useful in fabricating potential, QD-based nanoelectronic devices like quantum-dot cellular automata and spin exchange switches. However, since Ga is a p-type dopant in Si, patterning with Ga+ ions from a conventional liquid metal ion source (LMIS) leads to uncontrolled doping of the Si substrate. Moreover, Ga can behave as a surfactant during epitaxial growth of Si and Ge. In this work, we use electrically non-invasive ions for FIB-templated growth in order to avoid Ga doping and as a means to investigate fundamental mechanisms involved in templated nucleation of QDs. We employ a mass-selecting FIB and alloy LMISs to work with ions which are unobtainable from elemental sources. Ions of particular importance for non-invasive patterning include Si (obtained from a AuSi LMIS) and Ge (from a AuGeMn LMIS). In addition, the use of B ions (from an AsPdB LMIS) is explored as a potential method of producing auto-doped, templated QDs. These techniques are establishing a platform for nanoscale control of the formation, position and doping of epitaxial QD arrays of any desired complexity.