Improved resistivity of NiAl thin films at low temperature for advanced interconnect metallization

We investigate NiAl as a potential alternative for Cu in future interconnect metallization schemes. NiAl was deposited by physical vapor deposition at temperatures up to 420°C. A resistivity of 30 μΩcm was achieved for a 7 nm thick NiAl film at a deposition temperature of 420°C with in-situ Si capping at 100°C. A resistivity of 18 μΩcm was reached for 22 nm thick NiAl in identical conditions. Depositing epitaxial NiAl on Ge (100) led to an even lower resistivity of 14.3 μΩcm for a 22 nm film since better crystallinity was obtained. Challenges and integration feasibility are discussed.