Alternative A-gate structures for the realization of semiconductor quantum computers

Abstract

Two new A-gate structures for the realization of the qubit for the semiconductor quantum computer are proposed and investigated rigorously by a numerical simulation method. The coplanar A-gate structure has the advantage of easy fabrication, but it offers only a relatively weak voltage control over the nuclear magnetic resonance (NMR) frequency of the donor atom. However, this short-coming can be overcome by doping the donor closer to the substrate interface. The split-ground A-gate structure, on the other hand, produces a similar potential distribution as that of the original Kanes A-gate structure and provides a relatively stronger control over the NMR frequency of the donor atom. Both structures have the advantage of allowing device integration or heterostructure fabrication from below the silicon substrate. All simulations in this study are carried out by a rigorous electromagnetic simulation tool plus a quantum mechanical perturbation theory. © 2013 AIP Publishing LLC.