On demand spatially, controlled fabrication of single photon emitters in Silicon by liquid metal alloy ion source focused ion beam implantation

Single photon emitters (SPE) are fundamental building blocks for future quantum technology applications. However, many approaches lack the required spatial placement accuracy and Si technology compatibility required for many of the envisioned applications. Here, we present a method to place single or few SPEs emitting in the telecom O-band1. The successful integration of these telecom quantum emitters into photonic structures such as micro-resonators, nanopillars and photonic crystals with sub-micrometer precision paves the way toward a monolithic, all-silicon-based semiconductor-superconductor quantum circuit for which this work lays the foundations.
To achieve our goal, we employ home built AuSi liquid metal alloy ion sources (LMAIS) and an Orsay Physics CANION M31Z+ focused ion beam (FIB). Silicon-on-insulator substrates from different fabrication methods have been irradiated with Si++ 40 keV ions in a spot pattern of 6 to 500 ions per spot.
For the analysis and confirmation of the fabrication of true SPEs a home build photo luminescence setup has been used. G-centers formed by the combination of two carbon atoms and a silicon atom with a zero phonon lines (ZPL) at 1278 nm have been created in carbon rich SOI wafers. In ultra clean SOI wafers W-centers, a tri-interstitial Si complex has been created with a ZPL at 1218 nm. The achieved lateral SPE placement accuracy is below 50 nm in both cases and the success rate of SPE formation is more than 50%.
Finally, we give an overview on possible other applications and give an outlook on future projects and instrumentation developments.
1Hollenbach, M., Klingner, N., Jagtap, N.S. et al. Wafer-scale nanofabrication of telecom single-photon emitters in silicon. Nature Communications 13, 7683 (2022). https://doi.org/10.1038/s41467-022-35051-5