Diffusion and reactions in thin films

Atomic diffusion and reactions in thin films show some features not commonly found in bulk samples. The reasons for distinctive behaviour are reviewed: short length scales, unusual phase combinations, metastable phases, capability for rapid thermal processing, capability for chemical modification, and high stresses. For interaction between elemental layers, various processes are considered in relation to thermodynamic and kinetic parameters. For laser surface melting and subsequent rapid solidification, the important length scales are discussed.