AP01037 Investigation of Positive Ion Motion in Ar-N2 RF Plasma Using a Cylindrical Langmuir Probe

Abstract

This study presents a comparison of the Orbital Motion Limited (OML) and Allen-Boyd-Reynolds (ABR) models for describing positive ions behavior in low-temperature RF magnetron (Ar-N₂) plasma containing 70%, 60%, and 50% Ar in generated using 20W RF magnetron sputtering. Analysis performed on the I-V characteristics (0 to -40 V) obtained from a cylindrical Langmuir probe employed four criteria: a comparison of experimental and theoretical ion saturation current, the Sonin plot analysis, I²-V the linearity in the ion saturation region, and the Pilling-Carnegie criterion (d(log₁₀V)/d(log₁₀I)) versus V- V_plasma. The ABR model accurately predicted the experimental results for the first and second criteria. The OML model agreed with the third and fourth criteria. Although this agreement was limited for the fourth criterion at β=0.16, the third criterion  revealed increased linearity of the I²-V curve of Ar-N₂ plasma with 70%, 60% Ar, indicating better agreement with the OML model in the saturation region than the 50% Ar plasma. Fourth criterion (the Pilling-Carnegie) indicates good agreement with the OML model for β=0.08 and 0.1, but deviation occurs at β=0.16.