Design and Analysis of Copper and Aluminum Interconnects for All-Spin Logic

In this paper, a conventional spin-valve configuration combined with spin-torque-driven switching is used as an energy efficient interconnect structure for all-spin logic. Both Cu and Al interconnect materials are analyzed based on physical models for spin injection, spin transport, and magnetization dynamics. The results indicate proposed metallic interconnects dissipate less energy as compared with all-spin logic interconnects based on the nonlocal spin-valve configuration. Compared with a similar spin interconnect with an Si channel, the spin currents and injection efficiencies are predicted to be higher when a metal like Cu or Al is used due to no Schottky barrier at the interface. Because of the longer spin relaxation length (SRL) in Al as compared with Cu, the delay and energy dissipation are lower when Al is used especially at longer lengths where signal loss becomes important. While metallic spin interconnects are faster and more energy efficient in short lengths because of their smaller resistances and higher spin injection efficiencies, they are outperformed by spin interconnects with Si channels at long lengths because the SRLs in Si can be as long as many micrometers, whereas in metals they are limited to a few hundred nanometers.