Электрический потенциал изолированной подложки в плазменном потоке катодно-дугового разряда

Abstract

The high-current cathodic arc in vacuum as well as in acetylene atmosphere at pressures of 0.2 to 2 Pa used for diamond-like carbon coating deposition is considered. Two cylindrical isolated probes were used to measure the floating potential and velocity of plasma. It was found that the substrate is under accelerating potential of –(15÷35) V during the discharge, and the value of potential is essentially independent of the main discharge energy and substrate spatial position. There observed floating potential ripple with amplitude of up to 20 V and frequency of 100–200 kHz for the substrate (probe) near the cathode. With increasing distance from the cathode surface the amplitude and frequency of the ripple are reduced considerably, and this decrease is more pronounced for the discharge in acetylene atmosphere (at acetylene partial pressure of 0.2 Pa the ripple amplitude is 1–5 B).