화학공학소재연구정보센터
Applied Surface Science, Vol.200, No.1-4, 68-75, 2002
Ablation of molybdenum and niobium with a HyBrID copper laser
A hydrogen bromide in discharge (HyBrID) copper laser with 12 W of maximum average power, 16 kHz repetition rate and 35 ns pulse duration, emitting simultaneously in 512 and 578 nm, was used to study molybdenum and niobium ablation. A modified Balzer QMG-311 mass spectrometer was used for monitoring presence of metal vapor and a pair of polarized flat electrodes placed parallel to the metal vapor stream was used in order to observe electric charges formation. Thin films on BK-7 optical-quality flats allowed the estimation of deposition rate. The measured ablation thresholds of 6.9 and 5.4 J/cm(2) for Mo and Nb, respectively, agreed well with theoretical estimations. Charge formation was observed for laser fluencies below the vapor formation thresholds and this was attributed to thermoionic emission. The maximum film growth rate in our experimental facility was measured to be about 16 Angstrom/min for Mo and 11 Angstrom/min for Nb. (C) 2002 Elsevier Science B.V. All rights reserved.