Existing experimental data on the bulk conductivity of ${\mathrm{Ta}}_{2}$${\mathrm{O}}_{5}$ and SiO films are shown to be consistent with the Schottky effect rather than the Poole-Frenkel effect. A discussion of the physical properties of vacuum-deposited insulators has led to a simple model in which the insulator is proposed to contain neutral traps and donor centers. This model is shown to resolve the above-mentioned "anomalous" Poole-Frenkel effect. Other simple models are discussed, but they do not exhibit the anomalous Poole-Frenkel effect.

Poole-Frenkel Effect and Schottky Effect in Metal-Insulator-Metal Systems

Misfit dislocations are often transported to the interface between crystals by glide. In materials with the diamond or sphalerite structures, glide is inhibited by the Peierls stress. The aim of this paper is to present a theory for misfit accommodation which includes the effect of the Peierls stress. It is used to explain the elastic strains present in films of germanium on gallium asrenide and to explain the reduction of these strains by a high‐temperature anneal. The strains in germanium on gallium arsenide, and the effect of temperature upon them, are not explained by earlier theories for the accommodation of misfit between one crystal and another.

Accommodation of Misfit Across the Interface Between Crystals of Semiconducting Elements or Compounds

A statistical model for the reflection of scalar plane waves from a rough surface leads to a plane wave in the direction of specular reflection and to a contribution with a finite angular spread about that direction, depending on the tangential correlation of the surface asperities. Based upon on this result, a new semiclassical model, which satisfies the requirement of flux conservation, is proposed for the boundary condition for the distribution function of the size effect in the electrical conductivity. In the absence of correlation, the resultant expression replaces the constant specularity parameter p of Fuchs by the function exp[−(4π(h/λ) cosθ0)2] with θ0 the angle of the electron wave vector with the surface normal. Correlation produces an additional forward component within the diffuse contribution. Numerical results of the size effect for zero correlation are compared to the Fuchs model as well as a more recent model, and show a different thickness dependence for thin samples. The effect of correlation is to add to the conductivity, as a result of the diffuse contribution whose velocity has a finite expectation value in the direction of the current.

Statistical Model for the Size Effect in Electrical Conduction

A review is given of the evidence available on the mechanism of growth and the structure of thin deposited films. The main attention is devoted to the growth of metals onto single crystal substrates, particularly those formed by the evaporation technique. Some consideration of other types of deposit is also given, including chemically formed films and epitaxial silicon layers. A survey of the various experimental techniques which can be used for structural studies on thin films is given, but the main evidence presented is based upon electron diffraction and transmission electron microscopy. The mode of nucleation of the layers is described, and the evidence for the way in which the nuclei develop into a continuous deposit film is outlined. This includes the evidence obtained from growing films inside the electron microscope, which reveals two important processes. These are the ‘liquid-like’ coalescence of nuclei and islands, and recrystallization of islands. The various imperfection structures ob...

The nucleation, growth, structure and epitaxy of thin surface films

https://ris.utwente.nl/ws/files/6644857/Abelmann97oblique.pdf

H. Sato

Papers

Single-Crystal Films