A New Tool for Quantum Device Fabrication

July 10th 2018 — A new single ion implantation tool is launched at the UK National Ion Beam Centre. Part of a 3 year project between Ionoptika and the University of Surrey and funded by the EPSRC, the new instrument will enable researchers to create new quantum devices faster than ever before.

The instrument, named SIMPLE (Single Ion Multi-species Positioning at Low Energy), was launched during the 16th International Conference on Nuclear Microprobe Technology and Applications (ICNMTA2018) held at the University of Surrey (click here to read the press release).

Quantum Technology

Quantum mechanics – that fascinating and sometimes bizarre theory governing the world of the very small – has enormous potential to revolutionize many aspects of modern technology. More secure digital communication, “quantum safe” cryptography methods, more accurate time measurements, and faster, more powerful computers are all thought possible.

Quantum computers in particular are an exciting prospect — it’s expected that they will be capable of solving problems not currently feasible even by our most powerful super computers. Actually building a quantum computer, however, remains an hugely ambitious challenge.

One design for a quantum bit, or qubit – the basic building block of a quantum computer – was put forward by Bruce Kane in 1998. It involves embedding pairs of donor atoms, such as phosphorous, very close to one another (~ 20 nm) within a silicon lattice. Known as electron-mediated nuclear spin coupling, the idea has been successfully utilized by researchers to fabricate individual qubits.

Using a scanning tunneling microscope, researchers carefully placed individual P atoms using an atomically sharp tip and by stimulating chemical reactions on an atom-by-atom basis. An incredibly intricate technique, it can take several days of meticulous preparation to create just a single qubit. A remarkable feat, however a faster, more scalable method is clearly required.

Single Ion Implantation

The SIMPLE project was established with this objective – to develop an instrument platform for the reliable fabrication of arrays of qubits, with high speed and high precision, using single-ion implantation.

A well established technique in the semiconductor industry, the principles of large-scale ion implantation can be applied to implant individual ions when the parameters are very carefully controlled. Leveraging Ionoptika’s expertise in Ion Beam design and detection, an instrument platform was designed that is capable of producing an array of millions of implanted ions in just a fraction of a second.

The instrument comprises a highly focused, sub-20 nm mass-filtered ion column, a nano-precision stage, and high-sensitivity single ion implantation detection system. While detecting single ion events with high enough consistency for wide scale production remains a challenge, progress in this area has been encouraging, and confidence is high that this goal will be met. And when it is, it will mark a world first, and will usher in a new era of quantum computing.