Langmuir Probe Diagnostics of Low-pressure Inductively Coupled Argon Plasmas in a Magnetic Field

Plasma parameters of an inductively coupled radio frequency discharge in argon in an external axial magnetic field have been investigated at working pressures of 5×10−4–1×10−2 mbar and magnetic field of 0–80 G. Axial distributions of plasma density and electron temperature have been derived from Langmuir probe measurements. Plasma density monotonically increased with the increase in magnetic field at the highest pressure (1×10−2 mbar), whereas at lower pressures it reached its maximum (∼ 3×1011 cm−3) at a B-field ∼ 19 G. Plasma density was almost independent of the working pressure under low pressure regimes, which means that the degree of plasma ionization increased with the decrease in pressure reaching several percent at 5×10−4 mbar.