A non-volatile semiconductor storage device has a plurality of memory strings to each of which a plurality of electrically rewritable memory cells are connected in series. The method can include providing a substrate having a non-planar surface and depositing a first conformal dielectric layer on the substrate, the first conformal dielectric layer conforming to the non-planar surface of the substrate and having a non-planar surface. The methods generally include the steps of introducing a mesh into a blood vessel to capture embolic material, adjusting the mesh, if necessary, during the course of filtration, inflating the balloon occluder to occlude the vessel upstream of the mesh, and thereafter deflating the balloon occluder and removing the mesh and the captured foreign matter from the blood vessel. After forging and, optionally, annealing, hydridation and dehydridation treatments, the resulting material is subjected to nitriding.