| Title |
Stabilization of α-Ta by N2 Addition and Thermal Stability as a Diffusion Barrier |
| Authors |
배준우(Joon Woo Bae); 임재원(Jae Won Lim); (Minoru Isshiki) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Ta(N); α-Ta; Diffusion barrier; Ion beam deposition; Resistivity; Substrate bias voltage; Thermal stability |
| Abstract |
Ta and Ta(N) thin films were deposited on Si (100) substrate by an ion beam deposition method at various substrate bias voltage under Ar/N2 atmosphere in the different pressure ratio of Ar and N2. The effect of nitrogen concentration in Ta(N) on the surface morphology, crystalline microstructure, electrical resistivity was investigated. Furthermore, to examine the diffusion barrier property of Ta(N) films, Cu(100 nm)/Ta(30 nm)(with or without N2)/ Si structures were annealed at 550~700℃ for 30 min in H2 atmosphere. It was found that by adding nitrogen gas a metastable β-phase of Ta(N) films diminished, while a-phase stabilized. As a result, the Ta(N) films deposited at the substrate bias voltage of -50V under Ar/N2 atmosphere showed a good surface morphology and low resistivity. Concerning the thermal stability, the resistivity of Cu/Ta/Si structure considerably increased at 650℃. On the other hand, no change in resistivity and no evidence of a reaction between Cu and Si were observed for Cu/Ta(N)/Si structures annealed up to 650℃. This means that the thermal stability of Cu/Ta(N)/Si structures is improved by an addition of nitrogen. |