Tuesday, August 29, 2006

US Patent 7097708 - Donor Atoms For Quantum Computer


Quantum computing promises a new type of logic system for computers based not just on 0 and 1 but rather on a superposition of 0 and 1 allowing for enhanced parallel processing. The nuclear spin of phosphorus nuclei has been proposed as a potential way to enable quantum computing and this patent proposes the use of scanning tunneling microscope (STM) tips as a mechanism for placing the nuclei on a silicon substrate. Claim 1 reads:

1. A method of fabricating a nanoscale or atomic scale product, comprising the following steps: (a) preparing a clean silicon crystal surface; (b) passivating the surface with atomic hydrogen; (c) selectively desorbing single hydrogen atoms from the passivated surface using a STM tip to form a pattern of exposed areas in the hydrogen layer, where the areas are spaced from each other by 100 nm or less; (d) exposing the patterned surface to donor molecules to produce an array of single donor atom bearing molecules in the exposed areas; (e) annealing the arrayed surface at between about 300.degree. C. to about 650.degree. C. to incorporate electrically active donor atoms into the silicon.