The physical limits of CMOS scaling and the prohibitively high costs of future technology nodes, allows to foresee the end of further progress of CMOS technology in the near future and emphasizes the dire need to explore alternative technologies and computational principles. Spin as an alternative degree of freedom for computation and information storage attracts much attention due to its nonvolatility, high endurance, fast operation, and CMOS compatibility. Even though first promising results are available, these CMOS/Spintronic hybrid solutions are only competitive in comparison to conventional CMOS technology with respect to power consumption and speed – up to now - they are not able to compete in integration density. Due to the need of continuous conversion between the CMOS and the spintronic signal domain additional transistors are required, which rather leads to an integration density decrease than a densification of the circuit layout. This inspired us to avoid the signal conversion and carry out the complete device operation in the magnetic domain. The resulting non-volatile magnetic flip flop facilitates the spin transfer torque effect and magnetic exchange coupling for computation and thus enables an extremely dense layout. Instead of eight (non-clocked), twelve (clocked) or seven CMOS transistors and two magnetic tunnel junctions (CMOS/Spintronic hybrid) for a RS flip flop a footprint of only 10nmx40nm is sufficient. Additionally, the flip flop can be stacked to an extremely dense shift register.
The ERC Proof of Concept Project NOVOFLOP not only enabled us to further improve and develop the flip flop idea, but also to probe its commercialization potential and what is needed to bridge the gap towards market. Simulations showed that indeed the flip flops can be stacked to an ultra dense shift register and that the register is able to tolerate a moderate amount of variability. The for these simulations required micromagnetic model as well as the SPICE model for the flip flop's circuit level simulations has been published as open source to further push the idea and to serve as a seed for the familiarization of the next generation of engineers. In parallel a process for the manufacturing of the flip flops has been developed. The commercialization potential of the idea was tested by an application to the Science and Business Awards of the Rudolf Sallinger Fonds, where the (business) idea was ranked Top 10, and further evaluated and refined during the I.E.C.T. Hermann Hauser summer school event. Overall, the business idea to create a start-up that builds tailor-made solutions and licenses them to semiconductor companies was very well perceived and encouraged the preparation of an FFG Spin-off Fellowship in order to continue the work on the flip flop and the foundation of a company.
