AVS 60th International Symposium and Exhibition
    Advanced Surface Engineering Thursday Sessions
       Session SE-ThP

Paper SE-ThP2
Recycling and Diffusion of Ions in High Power Impulse Magnetron Sputtering Plasmas

Thursday, October 31, 2013, 6:00 pm, Room Hall B

Session: Poster Session
Presenter: L. Meng, University of Illinois at Urbana Champaign
Authors: L. Meng, University of Illinois at Urbana Champaign
P. Raman, University of Illinois at Urbana Champaign
H. Yu, University of Illinois at Urbana Champaign
D.N. Ruzic, University of Illinois at Urbana Champaign
Correspondent: Click to Email
***PLEASE NOTE THAT D. RUZIC CANNOT BE THE PRESENTER. HE IS ALREADY AN INVITED SPEAKER AND YOU MAY PRESENT ONE PAPER (ORAL OR POSTER) IN THE SYMPOSIUM*** In high power impulse magnetron sputtering (HiPIMS), ions either diffuse towards the substrate for the deposition or are recycled to sputter or self-sputter the target. Both processes were studied here to further understand the underlying mechanisms. For the diffusion, plasma across the entire chamber was characterized using a 3D scanning triple Langmuir probe. An obvious plasma expansion originated from the “race track” region was observed. The expansion speed and orientation varied with both pulsing parameters and magnetic field strength. These parameters were also found to affect the metal ionization fraction on the substrate. A lower magnetic field strength gave a higher ion fraction (e.g. up to 60% for Cu in a 200 Gauss field while about 30% in an 800 Gauss field) despite a lower plasma density. The corresponding lower plasma potential drop across the bulk plasma was accounted for the effect. Then, the fluxes of plasma species towards the cathode were directly measured through an orifice on the target. Quartz crystal microbalance and current collecting plate behind grid filters were used to determine the fluxes of argon ions, metal ions, and metal atoms. The self-sputtering effect during HiPIMS was supported by a higher fraction of metal ions obtained at a higher pulse peak current. A delayed detection of ion flux for 10 to 40 µs from the onset of pulse likely supported the theory of localization of ionization zone during the HiPIMS ignition.