Characterization of a template process for conducting cluster-assembled wires

Bismuth and antimony clusters have been deposited onto spin coated PMMA layers patterned by electron-beam exposure. The probability of reflection or adhesion of the clusters from the PMMA depended on its surface roughness, determined by the electron-beam exposure dose. The Bi and Sb clusters exhibited a significantly higher probability of reflection from unexposed PMMA than from Si₃N₄ (grown by plasma enhanced chemical vapor deposition) despite the approximately equal surface roughness of these layers. By exploiting this difference in adhesion/reflection, a cluster-assembled wire was grown between four-point planar electrodes. Four-probe electrical measurements yielded linear current-voltage (I(V)) characteristics whilst non-linear I(V) characteristics were obtained from two-probe measurements. An established model provided good agreement with two-probe conductance-voltage and resistance-temperature data. Tunneling barriers between the cluster wire and the planar electrodes are believed to have caused the non-linear two-point I(V) characteristics.     

Hafnium oxide thin films deposited from a filtered cathodic vacuum arc

The electrical and structural characteristics of hafnium oxide thin films reactively deposited from a filtered cathodic vacuum arc have been investigated. X-ray photoelectron spectroscopy was used to determine the deposition conditions (Ar/O₂ ratio) which produced stoichiometric HfO₂ films. Cross-sectional transmission electron microscopy showed that the micro-structure of the films was highly disordered with electron-diffraction analysis providing evidence for the presence of sub-nano-metre crystallites of the monoclinic HfO₂ (P2₁/c) phase. Further evidence for the presence of this phase was provided by measuring the O k-edge using electron energy loss spectroscopy and comparing it with calculations performed using FEFF8.2, a multiple scattering code. Surface imaging revealed that local film damage occurred in films deposited with substrate bias voltages exceeding −200 V. The current-leakage characteristics of the HfO₂ films deposited with a bias of approximately −100 V suggest that device grade HfO₂ films can be produced from a filtered cathodic vacuum arc.     

Job Satisfaction — A Study of Computer Specialists

Journal of the Operational Research Society -