IONIZED CLUSTER BEAMS - PHYSICS AND TECHNOLOGY

Ionized cluster beam (ICB) deposition has been used to form thin films of metals, insulators, semiconductors and organic materials which have unique characteristics when compared to films formed using other techniques. In addition, the use of gas-phase atoms in the form of accelerated clusters has recently shown promise for surface modification applications. A fundamental understanding of ICB deposition and related techniques requires investigations of (1) the mechanisms which lead to the growth of large vapor phase clusters, (2) techniques for determining the size distribution of large vapor clusters, (3) the initial stages of film nucleation, (4) film growth morphology related to lattice mismatch and ion beam parameters. Clarification of the role of clusters in ICB deposition has been greatly aided by atomic scale imaging by transmission electron microscopy and scanning tunnel microscopy in the early stages of film growth. Emphasis is given to the formation of high-quality, epitaxial metallic films. Several applications of ICB films with respect to microelectronics, optical mirrors, compound materials and organic materials are discussed with emphasis on the special characteristics of ICB films. Applications for gas-cluster processing are reviewed.