High-power pulsed magnetron sputtering (HPPMS) technology has drawn extensively attention for producing ultra-high dense plasma and high ionization fractions of the sputtered species,depositing dense films with high performance.CrNx films were deposited on the substrates of Si(100) using high-power pulsed unbalanced magnetron sputtering (HPPUMS) technology,and the analyses of XRD and atomic force microscope (AFM) were conducted on the properties of microstructure and surface morphology of CrNx films;the friction coefficient and the adhesion between CrNx film and substrate were measured,respectively.It was found HPPUMS discharge is able to deposit CrNx films with super comprehensive properties:higher adhesive strength between the film and substrate and lower coefficient of friction.Deposition rate of CrNx films,which was tested by interferometry,was about 4.2nm/min at 0.6Pa and the pulse power density up to 6.8kW/cm2 with the pulse repetition frequency of 0.7Hz,which is about 56% of that provided by the mid-frequency magnetron sputtering discharge under the conditions of the same average power output.However,clusters with a dimension of several hundred nanometers were observed on the AFM morphology probably related to high pulse current.
Mu Xiaodong,Mu Zongxin,Wang Chun,Jia Li,Zang Hirong,Liu Bingbing,Dong Chuang Key Laboratory of Materials Modification by Laser,Ion and Electron Beams (Dalian University of Technology),Ministry of Education,School of Physics and Optoelectronic Technology,Dalian University of Technology,Dalian 116024,China
High-power pulsed magnetron sputtering(HPPMS or HiPIMS) is an emerging coating technology that produces very dense plasmas and highly ionized sputtering atoms.This paper is focused on discharge properties,unbalanced features and temporal evolution of pulse current of the HPPMS discharge.A hollow cathode was used to suppress the scattering of charges.A coaxial coil surrounding the target was used to control the breakdown voltage and pulse repetition frequency by varying the coil current.A Langmuir probe and an oscilloscope were used to simultaneously measure the floating potential,pulse voltage and pulse current signals.The pulse power density in the discharge reached 10 kW/cm^2 with frequencies as high as～40 Hz and a pulse width about 1～5 ms.The characteristics of the discharge evolution were analyzed using magnetron discharge dynamics.
An experimental study of the effect of applied magnetic field on the properties of theplasma and electrostatic oscillations in an unbalanced magnetron sputtering discharge was carriedout. The apparatus consists of a magnetron sputtering target, using the conventional magneticfield configuration, and a coaxial coil around the target for an applied axial magnetic field, Thedependencies of plasma parameters on the coil current were studied by two Langmuir probes.The resonance properties of electrostatic oscillations were observed. The results indicate that theapplied magnetic field affects the plasma properties for the coil current in a range of 0 A to 8 A.The frequency bandwidth of the electrostatic oscillations in the unbalanced magnetron sputteringplasma is in a range of 0 kHz to 300 kHz. From the spectrum analysis, the eigenfrequency nearthe target is in a range of 20 kHz to 50 kHz under typical experimental conditions where all themagnetic field, pressure, and power etc are able to have full impact on the spectrum characteristics.The calculated value of the electron temperature as per an ion acoustic standing wave patterninside the magnetic trap is in good agreement with the experimental result.
