Films of ni-7 at% V, Pd, Pt and Ta-Si-N as diffusion barriers for copper on Bi2Te3

摘要

Films of Ni-7 at% V, Pt, Pd, and Ta40Si14N46, each approximately 100 nm thick, were magnetron-deposited and Interposed between about 250 nm thick copper overlayers and Bi2Te3 single-crystalline substrates. The samples were then annealed in vacuum up to 350 degrees C. The performance of the metal and the tantalum-silicon-nitride films as diffusion barriers for in-diffusion of Cu and out-diffusion of Bi and Te was evaluated by 2.0 MeV He-4 backscattering spectrometry and x-ray diffraction. The Ni-7 at%:V, Pd and Pt films all fail to prevent interdiffusion of Cu and Bi2Te3 after a few hours of annealing at 200 degrees C. However, the Ta40Si14N46 barrier preserves the integrity of the contact: after 250 degrees C for 50 h and 350 degrees C for 1 h anneals. These results confirm the superior characteristics of the metal-silicon-nitride films as diffusion barriers. [References: 19]