Fabrication and characterization of 2D and 3D perpendicular nanomagnetic devices with CoFeB/MgO ultrathin films

According to the International Technology Roadmap of Semiconductors (ITRS), the complementary metal-oxide-semiconductor (CMOS) technology era is reaching its technological and economical limits. Several new approaches and technologies are investigated by industry and academia with the aim to replace the CMOS technology or to implement hybrid integrated circuits (ICs). Among these, perpendicular Nanomagnetic Logic (pNML) seems to be very promising. This technology can combine memory and logic computing capability in the same device, giving the possibility to overcome the von Neumann bottleneck. pNLM exploits nanomagnets able to store digital binary information (1 and 0) encoded in their bistable perpendicular magnetization state (up/down), and to directly modify these magnetic states by magnetic field interaction between neighboring magnets. This work investigates the principles of pNML and proves the reliability of this new technology, focusing on a new magnetic material stack, Ta/CoFeB/MgO/Ta ultrathin film. This new stack should be more suitable than the previously investigated films, such as Co/Pt, Co/Ni, or Fe/Pt, for lower power and higher frequency logic operations. After the fabrication and characterization of the Ta/CoFeB/MgO/Ta magnetic structures, Focus Ion Beam (FIB) irradiation is performed to tune their magnetic properties, allowing to establish the correct coupling between the magnets and create working logic gates as inverters and majority voters. Design optimization is supported by micromagnetic simulations. Moreover, this thesis demonstrates the possibility to perform logic operations exploiting not only 2D architectures but also more complex and more performing 3D structures.