Study of TaN and TaN-Ta-TaN thin films as diffusion barriers in CeFe₄Sb₁₂ skutterudite

The efficiency of thermoelectric devices depends on phase stability of layers constituting the device. TaN and TaN-Ta-TaN thin films, 900 nm thick, were investigated as diffusion barriers for the CeFe₄Sb₁₂ thermoelectric substrate in contact with the Cu electrode. It is shown that Sb diffuses through the TaN layer when the sample is heated above 400 °C. Multilayer TaN-Ta-TaN acts as the diffusion barrier for Sb and is efficient up to 500 °C. When diffusion of Sb occurs above 400 °C for TaN and above 500 °C for TaN-Ta-TaN, the formation of FeSb₂ and Cu₂Sb precipitates was identified by XRD and TEM/energy dispersive X-ray spectroscopy.