Authors: S.R. Schofield, N.J. Curson, M.Y. Simmons, T. Hallam, F.J. Ruess, L. Oberbeck and R.G. Clark
Affilation: University of New South Wales, Australia
Pages: 68 - 71
Keywords: quantum computer, fabrication, silicon, lithography, STM, single atom
The ability to control the location of individual dopant atoms within a semiconductor has enormous potential for the creation of atomic-scale electronic devices. One of the most ambitious proposals for such a device is the solid-state quantum computer proposed by Kane, which requires the fabrication of a regularly-spaced array of individual P atoms as qubits, ~20 nm apart in a Si substrate. Here, we demonstrate the incorporation of individual P atoms into the surface of a Si substrate at controlled spatial locations, predefined with atomic-precision using a scanning tunneling microscope. A hydrogen monolayer was used as a lithographic resist, which was patterned by desorbing H from the surface with the STM tip. Phosphine precursor molecules were then adsorbed to the exposed areas of bare Si surface. The P atoms from these adsorbed molecules were then incorporated into the Si surface by performing a critical anneal to ~350 °C. Using this technique we demonstrate the creation of both continuous nanometer-wide lines of incorporated P atoms, and single P atom incorporation with a positional accuracy of order 1 nm. These results represent the first demonstration of controlled single dopant atom incorporation in Si at the atomic-scale.