tailieunhanh - Time resolved tdlas investigation of pre-ionization effect in dual HiPIMS discharges

We observed an enhancement of metastable density due to pre-ionization effect. It is shown that the peak density in the Cu pulse increases about 30% for the case of 15µs delay then decrease as the delay was prolonged. The effect displays even stronger in the peak density in the afterglow, as well as in the atom temperature behavior. Although metastable atoms are abundantly available in post-discharge, they play minor role in the ignition of the subsequence pulse. | Communications in Physics, Vol. 24, No. 3S2 (2014), pp. 45-51 DOI: TIME RESOLVED TDLAS INVESTIGATION OF PRE-IONIZATION EFFECT IN DUAL HiPIMS DISCHARGES NGUYEN VAN TAN AND DO HOANG TUNG Institute of Physics, Vietnam Academy of Science and Technology RAINER HIPLER Institute for Physics, University Greifswald, Felix-Hausdorff Strasse 6 17489 Greifswald, Germany E-mail: dhtung@ Received 20 June 2014 Accepted for publication 20 August 2014 Abstract. Time-resolved measurements have been performed during dual High Power Impulse Magnetron Sputtering (dual-HiPIMS) with two cathodes in a closed magnetic field configuration. The dual-HiPIMS system, operated at a repetition frequency f = 100 Hz and duty cycle of 1%, was equipped with two different metallic targets (Ti, Cu). Preionization effect of the Ti pulse on the Cu pulse was investigated through argon excited atom density and temperature by means of tunable diode laser absorption spectroscopy. We observed an enhancement of metastable density due to pre-ionization effect. It is shown that the peak density in the Cu pulse increases about 30% for the case of 15µs delay then decrease as the delay was prolonged. The effect displays even stronger in the peak density in the afterglow, as well as in the atom temperature behavior. Although metastable atoms are abundantly available in post-discharge, they play minor role in the ignition of the subsequence pulse. Keywords: HiPIMS; time resolved TDLAS; metastable, pre-ionization effect. I. INTRODUCTION Magnetron sputtering (MS) deposition is a plasma-based coating technique well known [1, 2] since 1980. Inert gas ions (usually Ar+ ) are accelerated to bombard cathode/target made from the material to be deposited. Sputtered target atoms condensate onto a substrate and form a film. Growth and formation of the film are strongly influenced by ion and energy fluxes to the substrate [3, 4]. High ionization degree of sputtered particles and .