The plasma over the racetrack in high power impulse magnetron sputtering develops in traveling ionization zones. Power densities can locally reach 109 W/m2, which is much higher than usually reported. Ionization zones move because ions are “evacuated” by the electric field, exposing neutrals to magnetically confined, drifting electrons. Drifting secondary electrons amplify ionization of the sameionization zone where the primary ions came from, while sputtered and outgassing atoms are supplied to the following zone(s). Strong density gradients parallel to the target disrupt electron confinement: a negative feedback mechanism that stabilizes ionization runaway.
BT - Applied Physics Letters C2 - LBNL-5685E DA - 05/2012 DO - 10.1063/1.4724205 IS - 22 N2 -The plasma over the racetrack in high power impulse magnetron sputtering develops in traveling ionization zones. Power densities can locally reach 109 W/m2, which is much higher than usually reported. Ionization zones move because ions are “evacuated” by the electric field, exposing neutrals to magnetically confined, drifting electrons. Drifting secondary electrons amplify ionization of the sameionization zone where the primary ions came from, while sputtered and outgassing atoms are supplied to the following zone(s). Strong density gradients parallel to the target disrupt electron confinement: a negative feedback mechanism that stabilizes ionization runaway.
PY - 2012 T2 - Applied Physics Letters TI - Self-organization and self-limitation in high power impulse magnetron sputtering VL - 100 ER -