28Si+ ion beams from Penning ion source based implanter systems for near-surface isotopic purification of silicon

Wear Behaviour of N Ion Implanted Ti-6Al-4V Alloy Processed by Selective Laser Melting

Selective laser melting (SLM) is a laser-based powder bed fusion additive manufacturing technique extensively used in industry. One of the most commonly used alloys in SLM process is Ti-6Al-4V. However, its tribological properties when coated with N ion implantation is not well understood. In the ion implantation process used in this study, N2+ and N+ are accelerated to the energy of 60 keV and implanted to a fluence of 6 × 1017 at.cm−2. The effect of N ion implanted layer in terms of hardness values and how this implanted layer may affect wear process and wear rate is investigated in this paper. Sliding wear tests were conducted on SLM and conventionally processed samples implanted with N ions, followed by examining the wear tracks and coefficient of friction in order to explain the wear rate data obtained. The results showed that N+ implantation increased hardness within the depth of ~200 nm and reduced wear rate in SLM samples, while N2+ was not beneficial.

A compact, ultra-high vacuum ion source for isotopically enriching and depositing 28Si thin films

An ultrahigh vacuum (UHV) compatible Penning ion source for growing pure, highly enriched ²⁸Si epitaxial thin films is presented. Enriched ²⁸Si is a critical material for quantum information due to the elimination of nuclear spins. In some cases, the material must be grown by low temperature molecular beam epitaxy, e.g., scanning tunneling microscopy hydrogen lithography-based devices. Traditional high-purity physical vapor methods typically deliver a very small fraction of source material onto the target substrate, making the cost for use with highly enriched source materials very high. Thus, directed beam sources provide an efficient alternative. This UHV Penning source uses all metal or ceramic parts and a removable electromagnet to allow bake-out. The source gas is a commercial (natural isotope abundance) silane gas (SiH₄), an inexpensive source material. High enrichment levels up to 99.999 87% (8.32 × 10^-7 mol/mol ²⁹Si) and high chemical purity of 99.965% are shown without postprocessing. We present and discuss the discharge properties of this new source, the ion mass spectrum when coupled to our mass filter, and the secondary ion mass spectroscopy of the grown films.