MobilNachhaltigTC Plattling MoMoZeitschriftenartikel
R. Janski, M. Fugger, Michael Sternad, M. Wilkening
Lithium Distribution in Monocrystalline Silicon-Based Lithium-Ion Batteries
ECS Transactions, vol. 62, no. 1, pp. 247-253
DOI: 10.1149/06201.0247ecst
Abstract anzeigen
The ability of nitrides and alloys of refractory metals to act as solid-state diffusion barrier for Li migration in Si was evaluated by mass spectrometry techniques. Magnetron sputtered barrier films on silicon, assembled in a Swagelok® half-cell, were used as working electrodes to determine whether several barrier layers are able to prevent the formation of Li-Si alloys. In addition, lithium ion diffusion was studied in monocrystalline silicon. To determine the depth profiles in the silicon substrate and in the barrier layer, respectively, two complementary techniques, being based on mass spectrometry, were applied: (i) ToF-SIMS was used as imaging technique for depth profiling the first microns and (ii) laser ablation ICP-MS was carried out to study depth profiles of up to hundreds of microns. Titanium nitride as well as tantalum nitride barriers turned out to prevent or inhibit the reaction between lithium and silicon. Regarding Li diffusion in silicon preliminary tests were performed to investigate both diffusion coefficients and the activation energies in (100) monocrystalline silicon.
MobilNachhaltigTC Plattling MoMoZeitschriftenartikel
R. Janski, M. Fugger, M. Forster, M. Sorger, A. Dunst, I. Hanzu, Michael Sternad, M. Wilkening
Lithium barrier materials for on-chip Si-based microbatteries
Journal of Materials Science: Materials in Electronics, vol. 28, no. 19, pp. 14605-14614
DOI: 10.1007/s10854-017-7325-4
Abstract anzeigen
The integration of lithium-ion batteries, featuring ultra-high discharge rates, directly into silicon-based semiconductor devices opens unique paths towards the development of new mobile micro-electronics applications. Nevertheless, the small and mobile lithium ions have to be confined within the battery area of the silicon chip, otherwise the nearby fine microelectronics devices will be irreversibly damaged. Hence, a barrier material that blocks Li+ transport from the active components of the battery into the surrounding crystalline Si is needed. Here we evaluated the capability of magnetron sputtered barrier films of nitrides and alloys of refractory metals to prevent lithium ion diffusion and, thus, the formation of Li–Si phases outside the battery area. In order to determine the Li profiles in the barrier layer and in the silicon substrate, time-of-flight secondary ion mass spectroscopy was applied for profiling the first microns. In combination with electrochemical testing it turned out that titanium nitride as well as tantalum nitride barriers are able to significantly block Li ion migration.
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