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Phosphorescent light emission was investigated upon irradiation of WF&-12/noble gas (Ar, Kr, Ne, Xe) mixtures by At-F excimer laser. The continuous, broadband phosphorescence emission originates from excited tungsten clusters. The phosphorescence ceased with increased Xe and H, concentrations. Xe inhibits the formation of tungsten clusters and H, quenches the phosphorescence. The H, quenching rate and the unperturbed phosphorescence lifetime were determined to be 2.8X lo4 mbar-t s-' and 23 ,us, respectively. The intensity dependence of phosphorescence on the WF, partial pressure shows a rising part, then a declining part, and finally an increasing part again. It was shown that the declining part can be interpreted by scattering of the emitted phosphorescence. The phosphorescence intensity was dependent on the noble gas/H, concentration ratio. This effect was explained in terms of the thermal conductivity of the WF&-$/noble gas mixture, which influences the lifetime of the activated subfluorides and, thus, the cluster formation and growth rate. The intensity of the laser beam had a nonlinear effect on the phosphorescent light intensity due to the nonlinearly coupled photolytical steps of WF, and of the subfluorides. 0 1995 American Institute of Physics.

Photolytic tungsten chemical vapor deposition by an ArF excimer laser from a WF6/H2/Ar gas mixture is a very complicated process with reactions occurring both in series and in parallel. In this article different reaction pathways were modeled and compared with experimental deposition rate data. The absorption cross section for WF6 was measured to 1.7×10−18 cm2 at the ArF excimer laser wavelength of 193 nm. From a rate equation model, it was concluded that the direct photolytic contribution to the deposition rate was negligible. Moreover, reduction of tungsten subfluorides by hydrogen atoms, formed in reactions between photolytically released fluorine atoms and molecular hydrogen, was also found to be negligible. However, photolysis in combination with various radical reactions generate a relatively high concentration of tungsten subfluorides (WF3, WF4, and WF5). Thermochemical calculations indicate that H2 reduction of tungsten subfluorides to solid tungsten, forming clusters in the vapor, is highly probable. Among the different cluster nucleation mechanisms polymerization of tungsten subfluorides seems to be an important step. This also explains the influence of WF6 partial pressure on the deposition rate.

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H-6 720 eg, Dôm tér 9 . , Hungary ABSTRZCT Besults of a systematic study on Q-switched nthy laser induced rrrn2 area transfer of supported titanium and chranium thin films and Ge/Se multilayer structures are reported. The appearance of the prints is governed by film-support adhesion and source-target spacing. Best quality prints are produced by ablating well adhering ntal films in close proximity ( spacing < 15 pm) to the target to be patterned. Transfer fran stacked elenntaxy layers as a source offers a unique possibility of depositing acinpound films by mixing the constituents and transferring the material onto the target substrate in a single step. INTIOJ1JcTIONThe transfer of thin absorbing films from a transparent support onto another target substrate in close proximity with single laser pulses (Laser Induced Forward Transfer = LIFT) offers a straightforward novel approach to surface 1-5,The advantages of this technique are quite obvious : there is no need for cciplicated gas handling and/or vacuiin systems ( in fact all studies reported have been perforrrd in air1or in vacuum5 ) and the propei±ies of the target substrate surface to be patterned have essentially no influence on the process . Although it is anticipated that in the ideal case a spatial resolution approaching the pm danain can be achieved the minflnum lateral dittensions of the patterns actually deposited lie beten 30 and 120 iirn1-5.As a first systematic study of the rather diverse processes involved in thin film ablation and concctnitant deposition by single laser pulses we reporb here on imi2-area processing of supported titanium and chromium thin films . We focus /i / on the role of the glass support film interface in governing the characteristics of both ablation and printing and hi! On tI depennce of irorphology and lateral dirrensions of the transferred patterns on target-source distance . We analyse the elerrentary events by caiiparing experirrental data with calculated temperature distributions in space and tine. The results of a canparative study on Ge/Se bilayer structures allow to clarify the role of the interface in rerroving the absorbing film these also allow to verify the validity of our ablation/deposition rrocèl for fluences not far frau threshold. As a powerful extension we show that LIFT from stacked elementaxy layers on a transparent support as sources offers the unique possibility of positing aaround films by mixing the constituents and transferring the material onto the target substrate in a single step. 2.EXPE REMENTAL'I sets of titanium films the substrates of which were cleaned differently, 150