Resonance hairpin and Langmuir probe-assisted laser photodetachment measurements of the negative ion density in a pulsed dc magnetron discharge
Magnetron sputtering and photodetachment systems for RHP-assisted photodetachment. For the LP measurements the microwave source and acquisition unit are replaced with the detection and acquisition circuitry shown in Refs. 3, 4, and 21.
(Color online) (a) Magnetic field configuration relative to the cathode target position (0 cm). The laser-beam line-of-sight and position of the RHP tips at 10 cm from the target are shown. The RHP and LP were also positioned at 6.5 cm from the target; (b) a close-up of the RHP.
Discharge voltage and current waveforms.
Time-evolution of the perturbation in the electron density measured by the RHP at positions (a) 6.5 cm from the target and (b) 10 cm from the target. The time is referenced to either the beginning of the on-time or the off-time depending on which trace is being viewed.
Negative ion and native electron densities for times during the pulse measured by both RHP and LP at 10 cm from the target. The errors in and determined using the Langmuir probe are ±20% and ±30%, respectively. The errors in and determined by the RHP probe are both ±10%.
Negative ion-to-native electron density ratio measured by both RHP and LP techniques at 10 cm from the target. The errors in for the LP and RHP are estimated to be ±16% and ±20%, respectively.
Article metrics loading...
Full text loading...