Hybrid-Optimal Control of Reactive Low frequency Discharge plasmas

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The purpose of the present study is to realize the quantitative control system of the carbon thin film at low gas temperature at low frequency discharge experimentally and theoretically, based on the microscopic collision processes. The main results are as follows:(1) RF discharges in CH_4/H_2 for carbon film deposition has been diagnosed by spatiotemporally resolved optical emission spectroscopy between 25 kHz < f < 20 MHz. The relation between the sheath width/self-bias and the driving frequency of the discharge has been newly investigated in detail. In comparison with the results in Ar, the width of the rapidly decreasing region of the sustaining voltage is narrower in CH_4/H_2 than in Ar, and the appearance of the large self-bias voltage close to 3 MHz is found out. It is concluded that these phenomena are due to the change of the predominant ions from H^+, to H^+_ with increasing of f.(2) Reejection of the deposited species from the surface by the ion impact has been observed from the spatiotemporal optical emission spectroscopy, when the frequency decreases from 20 MHz to 100 kHz, and the phenomena are discussed from the viewpoint of the hardness of the deposition film. The impact energy of the ion will be observable by Doppler shift measurement.(3) The method to analyze the ion energy distribution in the sheath region has been proposed by using the Boltzmann equation, and the validity of the method is examined in Ar glow discharges.(4) Modeling of the RF glow discharge in CH_4 has been developed.