Atomic-control placement of individual P atoms in Si for the fabrication of a quantum computer qubit array
S. R. Schofield, N. J. Curson, M. Y. Simmons, L. Oberbeck, T. Hallam, F. J. Ruess, and R. G. Clark
Centre for Quantum Computer Technology, AU
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.
NSTI Nanotech 2003 Conference Technical Program Abstract