MATERIALS PROCESSING BY GAS CLUSTER ION BEAMS

摘要

Gas Cluster Ion Beam (GCIB) processing is based upon the use of electrically charged cluster ions consisting of a few hundreds to a few thousands of atoms or molecules of gaseous materials and subsequently ionized. When these cluster ions are energized and impact a surface they deposit a high energy density in a very small and shallow volume of the material. This high deposited energy density produces strongly non-linear processes of sputtering and implantation which are fundamentally different from those which can be produced by monomer ions. This paper describes the fundamental principles and experimental status of GCIB processing as a new technique with promise for practical industrial applications. A review is presented of the theoretical and experimental characteristics of new gas cluster ion bombardment processes and of related equipment development. The impacts of accelerated cluster ions upon substrate surfaces impart very high energy densities at the impact site of individual clusters and produce non-linear processes that are not present in the impacts of individual atomic ions. These unique bombardment characteristics are expected to facilitate new industrial applications that would not be possible by traditional ion beam processing. Among these are shallow ion implantation, high rate sputtering, surface cleaning and smoothing, and low temperature thin film formation. For example, low damage atomic scale surface smoothing has been used for metals, dielectrics, superconductors and diamond films, SiC surfaces for SOR mirrors, development of high yield sputtering processes and thin multi-layer film coatings for reliable and durable optical filters.