%0 Journal Article
%T Electric field reduced charging energies and two-electron bound excited states of single donors in silicon
%A R. Rahman
%A G. P. Lansbergen
%A J. Verduijn
%A G. C. Tettamanzi
%A S. H. Park
%A N. Collaert
%A S. Biesemans
%A G. Klimeck
%A L. C. L. Hollenberg
%A S. Rogge
%J Physics
%D 2011
%I arXiv
%R 10.1103/PhysRevB.84.115428
%X We present atomistic simulations of the D0 to D- charging energies of a gated donor in silicon as a function of applied fields and donor depths and find good agreement with experimental measure- ments. A self-consistent field large-scale tight-binding method is used to compute the D- binding energies with a domain of over 1.4 million atoms, taking into account the full bandstructure of the host, applied fields, and interfaces. An applied field pulls the loosely bound D- electron towards the interface and reduces the charging energy significantly below the bulk values. This enables formation of bound excited D-states in these gated donors, in contrast to bulk donors. A detailed quantitative comparison of the charging energies with transport spectroscopy measurements with multiple samples of arsenic donors in ultra-scaled FinFETs validates the model results and provides physical insights. We also report measured D-data showing for the first time the presence of bound D-excited states under applied fields.
%U http://arxiv.org/abs/1107.2701v1