Particulate ejection in pulsed-laser deposition

摘要

Abstract: ction of sub-micron size particulates from a metal target as a result of the interaction of an excimer laser with a Pt target was investigated. To study the effect of laser fluence, particulates were collected on Pt films prepared on MgO(100) substrates over a fluence range of 0.83 - 3.3 J/cm$+2$/. Films were prepared at several substrate temperatures: 25$DGR@C, 350$DGR@C, 450$DGR@C, and 550$DGR@C, and under 0.05 Torr of an inert gas (Ar). It was found that, for a substrate temperature of 450$DGR@C, the Pt particulates would stick easily to the growing Pt film with little evidence for deformation. The size distributions and areal densities of the metal particulates were measured from low magnification scanning electron micrographs of the thin film surfaces prepared at 450$DGR@C and compared. In general, spherical particulates were produced with diameters ranging from about 0.05 to 1.0 $mu@m. The shape of the size distribution of particulates on the film surface was roughly constant radially outward from the plume center, although the magnitude of the particulates decreased from the plume center. As the fluence increased, the mean diameter of the particulates increased slightly (from 0.25 to 0.35 $mu@m) while the number density of particulates decreased by over two orders of magnitude (from 1.04 $MUL 10$+5$/ to about 1.0 $MUL 10$+3$/ particulates/cm$+2$/ per angstrom of film deposited) near the plume center.!21