Origin of the Laser-Induced Broad Band Luminescence from a WF₆/H₂/Ar Gas Mixture

Abstract

The origin of the ArF excimer laser induced luminescence from a WFJH/Ar gas mixture was investigated. The experiments prove that the emission originates from excited W clusters with a size of about 10-20 nm. The influence of the H 2 and Ar concentrations, the laser fluence and the repetition rate on the light intensity was studied.

Light emission from tungsten nanoparticles during laser-assisted chemical vapor deposition of tungsten

“…The agreement between the measured/corrected spectra and the Planck curves is very good so the conclusion is that the radiation emerging from WF 6 /H 2 /Ar ͑and therefore WF 6 /H 2 /noble gas͒ 8 mixtures, illuminated by ArF excimer laser, is blackbody-like and not phosphorescence as stated before. 8,10 Since it was proven that the broadband radiation originates from tungsten nanoparticles 6 it is obvious that the blackbody-like radiation comes from these nanoparticles.…”

“…7 Moreover, a broadband radiation was also observed and assigned to phosphorescence of tungsten nanoparticles. 6,8 In this work supplementary results to this broadband emission are presented, and it is shown that the phosphorescence is in fact a blackbody-like emission. This allows measuring the temperature of the hot particles heated by subsequent laser pulses following the particle formation.…”

“…The laser parameters were as follows; wavelength 193 nm ͑Lambda Physik ArF excimer laser͒, nominal pulse duration 15 ns full width at half maximum, repetition rate 50 Hz, and the laser fluence was set to ϳ110 mJ/cm 2 . The beam was slightly focused by a cylindrical lens with 38 cm focal length, the beam size was 1.5 cmϫ0.6 cm at the position of optical observation and deposition, which was 9 cm downstream from the WF 6 During experiments particles were deposited on carbon covered Cu grids for TEM analysis.…”

“…4,5 It was shown that for a wide range of parameter sets, the tungsten deposition goes through nanoparticle formation from WF 6 /H 2 /M (MϭAr, Kr, Ne, Xe) gas mixtures irradiated by an ArF excimer laser (ϭ193 nm). [6][7][8][9] This is due to gas phase reactions, since the laser beam is aligned parallel to and just above the substrate surface. For metallization purposes the particle formation is an avoidable effect, on the other hand, this LCVD process may be utilized for nanoparticle-film deposition.…”