Aligned Ion Implantation Using Scanning Probes: Towards Precise Single Ion Placement for a Solidstate Quantum Computer

A new technique for precise ion implantation has beendeveloped using a scanning probe that has beenequipped with a small aperture and incorporated intoan ion beamline. Ions are passed through the apertureand implanted into a sample. By using a scanningprobe the target can be imaged in a non-destructiveway prior to implantation. The probe can be placed atthe desired location with nanometer precision. With this approach a final placement accuracy ofabout 10 nm is envisioned, limited by straggling andthe aperture size. In this work a feature size downto 120 nm has been demonstrated. This research is part of a program for thedevelopment of test structures for a quantumcomputer. For this application the placement accuracyneeds to be increased and a detector for single iondetection has to be integrated into the setup. Boththese issues are discussed. To achieve single ion detection highly charged ionsare used, since the additional potential energyreleased by these ions on impact should lead to aneasier detection of each ion. The highly charged ionswere produced using a specialized ion source andtheir creation and interactions with solids aredescribed in detail.