NOVEL COMBINATORIAL METHODS FOR INORGANIC THIN FILMS.
Over the past decade, combinatorial chemistry, which involves high throughput synthesis and analysis of a multivariable "library" containing a large number of miniaturized samples, has revolutionized the drug discovery process in the pharmaceuticals industry. Recently, materials scientists have been applying combinatorial principles to the discovery and optimization of inorganic thin films for electronic, photonic, and magnetic devices; this requires unique tools for library fabrication and characterization. Researchers at NIST have developed a novel dual-beam, dual-target pulsed laser deposition process for the fabrication of compositionally-graded thin film libraries. The deposition system has high-speed, in situ diagnostics, which permit real-time fine-tuning of the two laser plumes to optimize the deposition parameters. This technique is applicable to a wide range of complex oxides, metals, and metal/oxide composites. To date, libraries of [BaTiO.sub.3][SrTiO.sub.3], a material of interest for wireless co mmunication devices, have been deposited on silicon substrates. Film thickness has been mapped at a spatial resolution of 0.3 mm using a spectroscopic reflectometry apparatus designed by NIST researchers. Composition and dielectric properties of the libraries are being characterized by high throughput measurement techniques.