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© 2019 IOP Publishing Ltd. Neutron scattering studies have been carried out on single crystal films of [001] orientated L10 ordered MnPt grown epitaxially on MgO (001) using DC magnetron sputtering. Polarized neutron diffraction studies at room temperature show that the moments in ordered MnPt are aligned perpendicular to the [001] axis with a tilt of 45° to the [100] axis and not parallel to [100] as inferred from previous powder neutron diffraction measurements.

In this study, PVD Ru-Mn composites were investigated in terms of major concerns that arise with the introduction of a new type of barrier. First, the Cu diffusion barrier performance after annealing at 600^oC and under subsequent BTS of +2MV/cm, 250^oC was investigated on SiO"2, and after 350^oC annealing on low-k dielectrics. Ru-Mn films proved to serve as outstanding Cu diffusion barrier over a wide range of Mn content. Second, the origin of the barrier performance was investigated using TEM, EELS and XPS depth profiling techniques, revealing the stuffing of grain boundaries as barrier mechanism. Third, Cu plating on damascene wafers applying a Ru-Mn seed layer was tested, and also the Cu adhesion thereon, resulting in a complete feature fill and excellent Cu wetting behavior. Fourth, the blocking of oxygen diffusion was examined, leading to a performance comparable to PVD TaN. Finally, the Mn content inside Ru was reduced down to 1at.% without compromising the superior material properties.

Co-sputtered Ru-Ta(N), Ru-W(N) and Ru-Mn composites are investigated in terms of their barrier properties against Cu diffusion. A wide range of stoichiometries is analyzed with regard to crystallization, barrier properties, resistivity, Cu adhesion and direct Cu plating behaviour. All films were annealed at 350^oC and 600^oC in forming gas for 1h and subsequently stressed at elevated temperatures and electrical fields (BTS, 250^oC, 2MV/cm, 30min). The leakage current was monitored during BTS to observe increased leakage due to Cu diffusion. The Cu ions that eventually have passed the barrier and drifted into the dielectric of the MIS test structure were detected and quantified using the triangular voltage sweep method. The addition of 10% W or Ta into a Ru film already leads to a highly improved barrier performance against Cu diffusion, comparable to TaN, as long as the temperatures involved are kept below 350^oC. Outstanding barriers were identified after 600^oC annealing and subsequent BTS, among them Ru"5"0W"5"0", Ru"5"0Ta"5"0 and Ru"9"5Mn"5. However, only Ru"9"0Ta"1"0 and Ru"9"5Mn"5 offer an excellent Cu adhesion and the possibility of direct Cu plating.

In this study Ru-Mn alloys are discussed in terms of some of the major questions that are typically associated with the development of new types of barriers. First, the Cu diffusion barrier performance after annealing at high temperatures and under subsequent bias temperature stress is investigated, on SiO 2 and on low-k dielectrics. Second, the origin of the barrier performance - either a self forming barrier caused by segregation of an alloyed element, or the stuffing of grain boundaries - is investigated, since this is of importance with regard to an electromigration barrier at the bottom of a via. Third, Cu plating and Cu adhesion behavior are addressed, since they are also important with regard to electromigration, specifically along the side walls of trenches. Fourth, the blocking of oxygen diffusion is investigated. Furthermore, down-scaling of the Mn content to a lowest possible level is pursued in order to reduce line and via resistances.

www.MaterialsViews.com C O M M U Self-Wound Composite Nanomembranes as Electrode Materials for Lithium Ion Batteries N IC A T By Heng-Xing Ji , Xing-Long Wu , Li-Zhen Fan , Cornelia Krien , Irina Fiering , Yu-Guo Guo , * Yongfeng Mei , * and Oliver G. Schmidt IO N Bending and rolling is commonly employed in nature to release strain in fi lms to maintain structure stability. Recently, rolledup nanotechnology has proven to be an intriguing approach on the micro-/nanoscale for various promising future applications and concepts. [ 1–5 ] Nanomembranes composed of various functional stacks can self wind (or roll up) into micro/nanotubes upon detaching from a holding substrate by releasing intrinsic differential strain. The deposition and process methods for nanomembranes are compatible to industrial-level technologies like e-beam evaporation, sputtering deposition and atomic layer deposition, etc., which are demanded by advanced materials used for applications. Moreover, the intrinsic strain accommodated in multi-layer nanomembranes is effi ciently released by self winding and thus offers a minimization of the system energy. [ 6 ] Such tubular and strain-relaxed structures are liable to improve the materials tolerance against stress cracking and are therefore promising candidates for increasing the stability of energy storage devices such as lithium ion batteries. Lithium ion batteries are attractive for applications ranging from electric vehicles to microchips. [ 7–10 ] One of the big challenges is strain accommodation during electrode lithiation, which would prevent the electrodes in batteries from being pulverized which causes capacity fading. [ 10–12 ] For example, transition-metal oxides and lithium alloys are attractive anode materials owing to their high theoretical charge capacity, which is several times larger than existing graphite anodes. [ 13–16 ]