The Fabrication of Arrays of Single Ions in Silicon via Ion Implantation
University of New South Wales 1014253 Australia
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Conventional computers are approaching fabrication limits where variation in the placement of single dopants greatly impacts performance. Fabricating a solid state SiP Kane architecture will require deterministic doping, the ability to accurately place dopants within a substrate. We have implemented an apparatus for creating arrays of single P donor atoms within Si. We model the fabrication of a three-donor device for demonstrating the coherent transfer by adiabatic passage transfer CTAP protocol and show that it can be done with deterministic ion implantation through a 20 nm nanostencil stepped 30 nm between implants to produce a yield of 1-in-7 well placed arrays. Single ion implantation is an established method of device fabrication that involves detecting single 14 keV P ions entering a substrate via the charge induced as the ion collides with the lattice. We have tested various designs for the single ion detector to evaluate the sources of good performance and achieved 984 counting efficiency with the classic design in high purity silicon. We have fabricated 200 nm think Si3N4 nanostencils with slot and hole shaped apertures as small as 20 nm using the focused ion beam FIB technique of back filling larger apertures with Pt. These adequately mask a 14 keV P ion to define the implant site. We have built apparatus that employs a piezo-positioner to move the nanostencil above the surface of a single ion detector. The fine alignment of the nanostencil to the implant site is performed using the ion impact signals as feedback over a patterned area of the detector and we have demonstrated this concept to a precision of sub-100 nm.
- Quantum Theory and Relativity
- Nuclear Physics and Elementary Particle Physics
- Computer Hardware