Nanoscale Al-Al and Cu-Cu Contacts

This paper reports that the forces needed to break Al and Cu native oxide are 0 to 3 muN, and 0 to 0.5 muN, respectively, remarkably less than the previously reported 0.1 N force requirement of breaking Al native oxide. Our modeling and experimental results indicate that nanoscale contact resistance is dominated by local hardening instead of contact force as in conventional contact theories. A microswitch featuring a 60 to 80 nm thick contact electrode is fabricated to demonstrate nanoscale Al contacts.