International Business Machines Corporation
ALUMINUM OXIDE PROTECED LITHIUM METAL TUNABLE 3D SILICON BATTERIES

Abstract:

One or more trenches in a silicon substrate have an electrically active surface at a trench base and metal layer disposed on the electrically active surface. Precursor materials are disposed and/or formed on the metal layer in the trench. An anode is patterned either exclusively in the 3D trench or in the 3D trench, sidewalls and field of the substrate, where the anode patterning transforms and/or moves the precursor materials in the trench into some novel compositions of matter and other final operational structures for the device, e.g. layers of metallic Lithium for energy storage and different concentrations of Lithium-silicon species in the substrate. A multi-faceted mechanism is disclosed for Al2O3 silicon interfacial additives. When the anode is patterned both in and outside the 3D wells, Al2O3 provides an for electron-conductive Li-metal interface that enables homogenous plating on both the insulated substrate field as well as active silicon trench base where Al2O3 acts as a barrier to Li--Si diffusion. When the anode is patterned only in the 3D trench, Al2O3 additive creates a robust, flexible, Li-permeable interface upon charge cycling, which preserves the 3D textured structure of the porous silicon anode. Additionally, the Al2O3 additive is mobilized deeper into the bulk silicon in parallel with Li+ and a conductive plasticizer upon progressive cycling--where the lithiated Al2O3 particles nucleate at defect sites and prevent mechanical degradation of the silicon anode through a combined bridge and spacer mechanism. By selecting different defined anode patterns to deposit on the 3D substrate, final operational characteristics, properties, structures, and charge storage performance for the device can be predictably designed and manufactured.