Deterministic ion implantation nears single donor level, detected by quantum transport measurement

While scientists would like to continue leveraging advances in silicon-based nanoelectronics, especially as future quantum computing demands increase, doing so now implies creating devices that require accurate control of both the position and the number of implanted donor atoms. A recent focused ion beam-based technique, combined with in situ single ion detection, addresses the issue and demonstrates single atom level doping, as reported in Review of Scientific Instruments.

The authors developed a system for deterministic single ion detection in conjunction with the nanoImplanter, a focused ion beam system at Sandia National Laboratory. An avalanche photo-diode detector containing the target nanostructure area within its detection region, where the patterned electrodes formed a single electron transistor for quantum transport measurements, allowed for single ion detection. The precision offered by the nanoImplanter provided targeting of implantation into the nanostructure within 35 nanometers. Short pulses of ions controlled the average number delivered to the region, and for fewer than one ion per pulse, the authors demonstrated targeted implantation of a single ion.

The process is compatible with current silicon electronics fabrication methods and could also be used in other precision fabrication techniques, such as creating vacancy centers in diamond for controlling the location of single photon sources.

This integrated process opens the door to developing single donor devices in silicon, as well as other materials using an ion implantation approach. According to the lead author Jose Pacheco, future research will include the challenging task of developing multiple coupled single atom devices.

Source: “Ion implantation for deterministic single atom devices,” by J. L. Pacheco, M. Singh, D. L. Perry, J. R. Wendt, G. Ten Eyck, R. P. Manginell, T. Pluym, D. R. Luhman, M. P. Lilly, M. S. Carroll, and E. Bielejec, Review of Scientific Instruments (2017). The article can be accessed at https://doi.org/10.1063/1.5001520 .