The dependence on thickness of breakdown phenomena in thin dielectric films is considered, using the theory which attributes breakdown to electron ionization avalanche. On the basis of the electron‐lattice scattering mechanism in dielectric materials and the electron behaviour in the conduction band of the dielectric, the ionization avalanche probability is derived and the current density evaluated by considering the tunnel‐effect injection of electrons at the negative bias contact. It is assumed that breakdown occurs when the current density, at some point within the dielectric layer, reaches a particular value which depends upon the dielectric under consideration. The correlation between breakdown field strengths and thicknesses agrees satisfactorily with published experimental results. The results derived are applicable to an estimate of the temperature of electrons injected by a tunnel cathode of the metal‐dielectric‐metal type.

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Thick film resistors are widely used in microelectronic devices, however the mechanism of electrical conduction in these resistors has not yet been fully understood. In particular the anomalous behaviour of the temperature coefficient of resistance (T.C.R.) vs. temperature for a purely ohmic resistor has not been explained. The anomaly is that the T.C.R. is negative at low temperatures, is zero around room temperature and becomes positive at higher temperatures. This paper demonstrates that the electrical conduction mechanism in thick film resistors can be described by the electron percolation theory already proposed to explain charge transport in amorphous semiconductors. The thick film structure consists of conductive grains with a diameter of 0.1 m to 0.3 m separated by dielectric layers.

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The electrical characteristics of ruthenium-based thick-film resistors with different conductive terminations (PtAu and Ag based compositions) and with different aspect ratios were examined. The purpose is to understand the effects of resistivity decrease and TCR variation caused by the migration of metal particles from the terminations into the resistor film.The majority of the data were collected by using silver-based terminations since Ag diffusion processes, and then the relevant electrical effects, are emphasized.Scanning electron microscopy, electron microprobe analysis and X-ray diffraction analysis have been used to analyze the diffusion processes and the thick-film microstructures. It is shown that the experimental data is simply explained by a conduction model which assumes percolative tunneling of electrons through conductive grains embedded in the glass matrix of the resistors. Using simple hypotheses the model theory gives a good quantitative fit of the experimental results.