The rise of devices using the 3rd dimension, and especially of memories, requires the development of processes to produce architectures in three dimensions. This is the key that is currently enabling flash memories to increase their competitiveness against hard disk drives. As regards the concept of a magnetic domain-wall-based race-track memory, it is required that physical segments are created regularly along the depth of a material, to bound domain walls at specific locations in a digital fashion, to be fault-tolerant.
SmartMembranes GmbH has developped a series of etching processes featuring variations of anodization voltage. Diameters from several tens of nanometers to 150 nm and beyond are achieved while retaining a long range pore ordering; in addition, variations in the pore structure along the length have been demonstrated. Such local protrusions or constrictions can be repeated several times over the typical alumina template thickness of several tens of micrometers. Furthermore, the distance between these diameter modulations can be tuned from a few hundreds of nanometers to several micrometers.
This state-of-the-art development will for sure enable new physics to be investigated, and provides a useful building block for the development of 3D devices, based on magnetic materials and beyond.
The following scanning electron micrographs illustrate the proficiency of SmartMembranes in these fabrication processes: