Silicon Atomic Quantum Dots Enable Beyond-CMOS Electronics - Field-Coupled Nanocomputing: Paradigms, Progress, and Perspectives - page 48

molecules have been rendered to conduct electrical current, molecular decom-
position has promptly occurred. We are considering initiating what could be
considered as “phase 2” of molecular electronics. By building artificial molecules
where and as needed, and by precisely building contacts also, it is possible to
ensure interactions and properties are exactly as designed. Working only with
the limited palette described here, it is evident that artificial molecules of diverse
properties can be designed and made in place. Networks of high complexity and
function can be formed. At the cost of greater fabrication complexity, for exam-
ple through the addition of atoms other than H and Si, a far broader range
of properties will be available. It is anticipated that ecient substrate coupling
will diminish decomposition pathways and that artificial molecules as envisioned
here will not fail as organics will as a result of undesired excitation and heating.

7 Instrumentation and Custom Lithography to Make

Prototype QCA Circuitry

State of the art instrumentation is required to make advances in this area. Years
of ordinary STM investigations were hampered by at least two problems. One
is non-ideal scanning and fabrication control something we will refer again to in
the next section. The other aspect is a lack of a bridge between the atom sale
and the macro scale.

Fig. 16. A crystalline Titanium Silicide island on a silicon substrate. Crucially, the
silicide-silicon boundary is atomically abrupt. The silicon nearby is well ordered as
required. Ultra fine extensions from such contacts with linear wire structures com-
posed of closely spaced ASiQDs will enable precise electrostatic addressing of atomic
structures.