No abstract

Ta/Si (100) and Cu/Ta/Si (100) film structures were fabricated by using ion beam deposition with a modified RF sputter-type ion source, in which a strong RF discharge was introduced in order to enhance the plasma density. For Ta/Si structures, Ta films were deposited at various bias voltages. When the substrate bias voltage was not applied, the Ta film showed a columnar structure and had a high resistivity of 2600 n m. On the other hand, when the substrate bias voltage of −50-−200 V was applied, the cross-sectional observation did not show columnar structure at all. In this case, film deposition was considered to be sufficient migration energy by the accelerated Ta + ions. In particular, Ta films deposited at a bias voltage of −125 V had a very small resistivity of 360 n m. Thermal stability of Cu(100 nm)/Ta(50 nm)/Si films, where Ta plays a role of diffusion barrier, was evaluated after annealing in H 2 atmosphere for 60 min at various temperatures. Non-columnar structure Ta films deposited at substrate bias voltages of −50 V and −125 V were found to be stable up to 600 • C, while columnar structure Ta films deposited at zero bias voltage degraded at 300 • C. This result indicates that the thermal stability of the Ta films is mainly governed by the film microstructure of the deposited layer.

No abstract

Abstrucf-High purity RF-sputter type metal ion source has been developed for non-mass separated ion beam deposition. Fe or Cu rod target of purity 99.999 YO or 99.9999%, respectively, was DC-sputtered inside an RF inductively generated Ar plasma. Optical emission specfroscopy from the plasma region (Fe case) indicated that emission from Fe* becomes larger than that of Ar* when DC bias voltage of -1 kV was applied. This result agreed with our previous mass spectroscopic that Fe+ ion intensity overcomes that of Ar+ because of an efficient Penning ionization of sputtered and evaporated Fe particles. Cu f h s deposited on Si substrate at RT with the ion source showed noncolumnar structure at a substrate bias voltage of -150 V, whereas only columnar structure was obtained with no bias voltage. This tendency qualitatively agreed with the case of Fe fdm formation obtained in our mass separated IBD.

No abstract