Work function of metals

Special aspects of diffusion in thin films

Thin film metallization of oxides in microelectronics

An analysis of the measurement of grain‐boundary diffusion at low temperatures by the surface‐accumulation mehod was carried out. In this method atoms are allowed to diffuse along grain boundaries from a source to a free surface where they spread out, accumulate, and are measured. The diffusion is carried out at low temperatures so that only the grain boundary and surface ’’short‐circuit paths’’ are active, and lattice diffusion is frozen out. This method is generally more sensitive than the depth profiling method for measuring grain‐boundary diffusion at low temperatures. However, the kinetics of the surface accumulation are strongly dependent on the nature of the source and sink. Treating the surface as a sink of finite capacity with a finite diffusion coefficient, diffusion analyses were developed for either a constant or an instantaneous source. Two dimensionless parameters, G and H, play important roles in determining the form of the solutions. H involves the ratio of grain‐boundary capacity to surfa...

Measurement of grain‐boundary diffusion at low temperatures by the surface accumulation method. I. Method and analysis

A tabulation and classification of the structures of clean solid surfaces and of adsorbed atomic and molecular monolayers as determined from low energy electron diffraction patterns

The role of diffusion in limiting the reliability of substrate bonding for bimetallic Cr–Au thin films was investigated using work function, Auger electron spectroscopy, and LEED measurements to characterize the structure and chemical composition of these films. The diffusion rates for Cr into Au films are measured by means of a new technique utilizing the change in electronic work function as a measure of the surface concentration change. It was found that the diffusion coefficient (D) depended on the deposition rate of the Au film, with a twofold increase in deposition rate giving rise to an order of magnitude increase in D. The presence of sulfur as an impurity in the Cr also had a significant effect on D. Comparison of these results with values of D obtained on Cr–Au films by other workers give similar activation energies, but much lower values of D0 (temperature independent part of D) were obtained in this work. The effect on the lifetimes of devices using thin bimetallic films is discussed in terms ...

G. A. Haas

Papers

Diffusion measurements in thin films utilizing work function changes: Cr into Au