The pre-ionized 60 MHz very-high-frequency （VHF） magnetron discharge at low pressure, assisted by inductively coupled plasma （ICP） discharge, was developed. The measurement of ion flux density and ion energy to th...The pre-ionized 60 MHz very-high-frequency （VHF） magnetron discharge at low pressure, assisted by inductively coupled plasma （ICP） discharge, was developed. The measurement of ion flux density and ion energy to the substrate was carried out by a retarding field energy analyzer. The electric characteristics of discharge were also investigated by voltage-current probe technique. It was found that by reducing the discharge pressure of VHF magnetron discharge from 5 to 1 Pa, the ion flux density increased about four times, meanwhile the ion energy also increased doubly. The electric characteristics of discharge also showed that a little improvement of sputtering effectiveness was achieved by reducing discharge pressure. Therefore, the deposition property of VHF （60 MHz） magnetron sputtering can be improved by reducing the discharge pressure using the ICP-assisted pre-ionized discharge.展开更多
Ar/N2/CH4 glow discharge at low-pressure are studied in a closed system. The plasma was produced in 79.6% N2-15.4% Ar- 5.0% CH4 ternary mixture at pressures between 0.5 and 10.0 Torr. The diagnostic has been made by o...Ar/N2/CH4 glow discharge at low-pressure are studied in a closed system. The plasma was produced in 79.6% N2-15.4% Ar- 5.0% CH4 ternary mixture at pressures between 0.5 and 10.0 Torr. The diagnostic has been made by optical emission spectroscopy （OES）. The principal species observed were： N2, N2＋, CH＋, CN, C2, C3, HI3, Ha, C＋ and At. It presents the behaviour of the bands and lines intensities as a function of the pressure. Also, it displays the ratios of intensities of N＋2 （391.44 nm）, CN （392.08 nm）, and H （486.13 nm） to that of the N2 （337.13 rim） as function of pressure. The ratios show a slow decreasing behavior as a function of the pressure. Being the CH/N2 ratio more highest and H/N2 ratio the lowest one. The variations of excited species at different pressures may change the subsequent chemical reactions in the gas phase significantly. The present results suggest that the ion-molecule and molecule-molecule reactions in the gas phase are likely to play a dominant role in the present pressures.展开更多
The generation and propagation of a streamer is a significant physical process of air gap discharge. Research on the mechanism of streamers under low-pressure conditions is helpful for understanding the process of lon...The generation and propagation of a streamer is a significant physical process of air gap discharge. Research on the mechanism of streamers under low-pressure conditions is helpful for understanding the process of long-gap discharge in a high-altitude area. This paper describes laboratory investigations of streamer discharge under alternating current（AC） voltage in a low pressure test platform for a 60 cm rod–plane gap at 30 kPa, and analyzes the characteristics of streamer generation and propagation. The results show that the partial streamer and breakdown streamer all occur in the positive half-cycle of AC voltage near the peak voltage at 30 kPa. The partial streamer could cause the distortion of current and voltage waveform, and it appears as the branching characteristic at the initial stage. With the extension of the streamer, the branching and tortuosity phenomena become gradually obvious, but the branching is suppressed when the streamer crosses the gap. The low-pressure condition has little influence on the tortuosity length and the tortuosity number of the streamer, but affect the diameter of streamer obviously.展开更多
基金supported by National Natural Science Foundation of China (Nos. 11675118 and 11275136)
文摘The pre-ionized 60 MHz very-high-frequency （VHF） magnetron discharge at low pressure, assisted by inductively coupled plasma （ICP） discharge, was developed. The measurement of ion flux density and ion energy to the substrate was carried out by a retarding field energy analyzer. The electric characteristics of discharge were also investigated by voltage-current probe technique. It was found that by reducing the discharge pressure of VHF magnetron discharge from 5 to 1 Pa, the ion flux density increased about four times, meanwhile the ion energy also increased doubly. The electric characteristics of discharge also showed that a little improvement of sputtering effectiveness was achieved by reducing discharge pressure. Therefore, the deposition property of VHF （60 MHz） magnetron sputtering can be improved by reducing the discharge pressure using the ICP-assisted pre-ionized discharge.
文摘Ar/N2/CH4 glow discharge at low-pressure are studied in a closed system. The plasma was produced in 79.6% N2-15.4% Ar- 5.0% CH4 ternary mixture at pressures between 0.5 and 10.0 Torr. The diagnostic has been made by optical emission spectroscopy （OES）. The principal species observed were： N2, N2＋, CH＋, CN, C2, C3, HI3, Ha, C＋ and At. It presents the behaviour of the bands and lines intensities as a function of the pressure. Also, it displays the ratios of intensities of N＋2 （391.44 nm）, CN （392.08 nm）, and H （486.13 nm） to that of the N2 （337.13 rim） as function of pressure. The ratios show a slow decreasing behavior as a function of the pressure. Being the CH/N2 ratio more highest and H/N2 ratio the lowest one. The variations of excited species at different pressures may change the subsequent chemical reactions in the gas phase significantly. The present results suggest that the ion-molecule and molecule-molecule reactions in the gas phase are likely to play a dominant role in the present pressures.
基金supported by National Natural Science Foundation of China (Grant No.51277063)
文摘The generation and propagation of a streamer is a significant physical process of air gap discharge. Research on the mechanism of streamers under low-pressure conditions is helpful for understanding the process of long-gap discharge in a high-altitude area. This paper describes laboratory investigations of streamer discharge under alternating current（AC） voltage in a low pressure test platform for a 60 cm rod–plane gap at 30 kPa, and analyzes the characteristics of streamer generation and propagation. The results show that the partial streamer and breakdown streamer all occur in the positive half-cycle of AC voltage near the peak voltage at 30 kPa. The partial streamer could cause the distortion of current and voltage waveform, and it appears as the branching characteristic at the initial stage. With the extension of the streamer, the branching and tortuosity phenomena become gradually obvious, but the branching is suppressed when the streamer crosses the gap. The low-pressure condition has little influence on the tortuosity length and the tortuosity number of the streamer, but affect the diameter of streamer obviously.
