Table of contents

The experimental data on nucleon-alpha reactions to discrete and continuum states are reviewed, together with the theories that have been proposed to account for them. At low energies the compound-nucleus mechanism predominates, and as the energy increases the pre-equilibrium and direct processes become more likely. These theories are described and the results of typical calculations compared with the experimental data. Particular attention is devoted to J-dependent and spectator effects, and to the competition between the triton pick-up and alpha knock-out mechanisms.

This paper provides an overview on the current understanding of electromigration in metals. The discussion is first focused on studies in bulk metals and alloys. This part includes a thermodynamic formulation of electromigration, a kinetic analysis of the atomic processes and a review of the theory. In addition, experimental results in interstitial and substitutional systems are summarised. The second part of the paper reviews the studies in metallic thin films. This emerged as an important area of electromigration studies since the late 1960s when electromigration damage was found to cause failure of conductor lines in integrated circuits. The discussion will review first the basic nature of electromigration in thin films with emphasis on the role of grain boundaries in mass transport and damage formation. Then the materials issues of electromigration will be explored according to the scaling trends in VLSI technology. Finally, the recent results of electromigration in fine lines and device contacts of dimensions in the micrometre range are discussed.

The manufacture of complex integrated circuits demanded by present-day system designers requires the assembly of a large number of interacting process steps. Many of these process steps cannot be chosen without considering the effect of the other steps involved in the manufacturing process. A great deal of understanding of the basic physical principles must be employed before a successful manufacturing process can be defined. The optimisation of the steps and their timely introduction to enable the device to enter the marketplace dictates that an efficient means of predicting the impact of a particular recipe must be employed. This review surveys the various physical principles that underly the processing steps, highlights some of the anomalous behaviour that occurs and describes the tools currently available to help the process physicist design diffusion, oxidation, ion implantation, deposition and photo-lithographic routines. An example of the use of these tools, and an indication of forthcoming developments, will be given.