The structure and properties of metal-semiconductor interfaces

Using the approach of Finnis and Sinclair, N-body potentials for copper, silver, gold and nickel have been constructed. The total energy is regarded as consisting of a pair-potential part and a many body cohesive part. Both these parts are functions of the atomic separations only and are represented by cubic splines, fitted to various bulk properties. For the noble metals, the pair-potentials were fitted at short range to pressure-volume relationships calculated by Christensen and Heine so that interactions at separations smaller than that of the first-nearest neighbours can be treated in this scheme. Using these potentials, point defects, surfaces (including the surface reconstructions) and grain boundaries have been studied and satisfactory agreement with available experimental data has been found.

Simple N-body potentials for the noble metals and nickel

Ion beam crystallography of surfaces and interfaces

Adsorbed layer and thin film growth modes monitored by Auger electron spectroscopy

Continuous and planar single-crystal NiSi2films (<60 A thick) have been grown on Si(100) and (111) by ultrahigh-vacuum techniques. Nickel deposition (<20 A) on atomically clean Si at room temperature, followed by low-temperature heating at ~450°C, results in the growth of epitaxial NiSi2 films whose structure depends critically on the starting Ni thickness. The films are coherent, without misfit dislocations. The orientation of the (111) silicide can be controlled by the initial Ni thickness.

Formation of Ultrathin Single-Crystal Silicide Films on Si: Surface and Interfacial Stabilization of Si-NiSi2Epitaxial Structures

Deuterium adsorption on the clean Si(111)–(7×7) surface was quantitatively studied by determining the absolute coverage as a function of exposure using nuclear microanalysis. The coverage was correlated with structural changes seen by low energy electron diffraction and the high energy ion scattering surface peak. A saturation coverage of 1.25±0.13 monolayers was established for activated deuterium adsorption.

Hydrogen adsorption on Si(111)–(7×7)

Epitaxy of Au on Ag(111) studied by high-energy ion scattering

Ni on Si(111): Reactivity and Interface Structure

We have studied the Si(111) surface after various heat treatments with small amounts of Ni (?1 monolayer) present. We find that three types of reconstructions can be obtained: 7×7, ’’1×1’’ and √19×√19. Photoemission spectra show that the metallic nature of the dangling bond surface state, characteristic of the clean 7×7 surface, disappears for the ’’1×1’’ and √19×√19 surfaces. MeV ion scattering establishes that the average surface atom displacement parallel to the surface is significantly larger for the √19×√19 surface than for both the clean 7×7 and the ’’1×1’’ surfaces.

R. J. Culbertson

Papers

Hydrogen adsorption on Si(111)–(7×7)

Epitaxy of Au on Ag(111) studied by high-energy ion scattering

Ni on Si(111): Reactivity and Interface Structure

Si(111): Ni surface studies by AES, UPS, LEED, and ion scattering

Summary Abstract: Au/Ag(111) epitaxy: Ion scattering and Auger analysis