Strategies for triple-donor devices fabricated by ion implantation
  Triple donor devices have the potential to exhibit adiabatic tunneling via the CTAP (Coherent Tunneling Adiabatic Passage) protocol which is a candidate transport mechanism for scalable quantum computing. We examine theoretically the statistics of dopant placement using counted ion implantation by employing an analytical treatment of CTAP transport properties under hydrogenic assumptions. We determine theoretical device yields for proof of concept devices for different implant energies. In particular, we determine a significant theoretical device yield (~80%) for 14keV phosphorus in silicon with nominal 20nm spacing. 
Jessica A. Van Donkelaar, Andrew D. Greentree, Lloyd C. L. Hollenberg   and David N. Jamieson