Scaling of ion implanted Si:P single electron devices

We present a modelling study on the scaling prospects for phosphorus in silicon (Si:P) single electron devices using readily available commercial and free-to-use software. The devices comprise phosphorus ion implanted, metallically doped (n+) dots (size range 50?500?nm) with source and drain reservoirs. Modelling results are compared to measurements on fabricated devices and discussed in the context of scaling down to few-electron structures. Given current fabrication constraints, we find that devices with 70?75 donors per dot should be realizable. We comment on methods for further reducing this number.