Contribution to the application of the Langmuir probe technique for plasmamonitoring in the Ar and n-hexane mixture plasma during the polymerisationprocess

In the present paper the Langmuir probe technique was applied for plasma mo nitoring in the Ar and n-hexane mixture plasma during the polymerisation pr ocess. The experiments were performed in a stainless steel DC: magnetron re actor with a planar magnetron cathode. Within the investigated range of the gas pressure, no time-stable condition of the discharge was found. The reg ular oscillations, of a frequency of approximately 32 kHz, were observed in the Ar and 20 % n-hexane mixture at the total pressure of 10 Pa and the di scharge current of 8 mA. The experimentally obtained probe characteristics were used to determine the density and the average energy of electrons. In the DC magnetron stainless steel reactor the electron average energy in the Ar and n-hexane mixture plasma was about one order of magnitude smaller th an in the case in which the working gas inside the reactor was the pure Ar. The probe measurements in the magnetron reactor were supplemented by the ex periment in the customary glass discharge tube with a hollow cathode. In th e glass discharge tube and in the Ar and 10% n-hexane mixture plasma a regi on of plasma parameters was found, in which the plasma was stable and no in stabilities were observed. At such conditions the experiments in the glass discharge tube were used for the study of the efficiency of the probe surfa ce cleaning methods used.