Deposition of Diamondlike Carbon Film and Mass Spectrometry Measurement in CH4/N2 RF Plasma
Author: Mutsukura, N.
Source: Plasma Chemistry and Plasma Processing, Volume 21, Number 2, June 2001 , pp. 265-277(13)
Abstract:The deposition of diamondlike carbon (DLC) film and the measurements of ionic species by means of mass spectrometry were carried out in a CH_4/N_2 RF (13.56 MHz) plasma at 0.1 Torr. The film deposition rate greatly depended on both CH_4/N_2composition ratio and RF power input. It was decreased monotonically as CH_4 content decreased in the plasma and then rapidly diminished to negligible amounts at a critical CH_4 content, which became large for higher RF power. The rate increased with increasing RF power, reaching a maximum value in 40% CH_4plasma. The predominant ionic products in CH_4/N_2 plasma were NH^+_4 and CH_4N^+ions, which were produced by reactions of hydrocarbon ions, such as CH^+_3, CH^+_2, CH^+_5, and C_2H^+_5with NH_3 molecules in the plasma. It was speculated that the production of NH^+_4 ion induced the decrease of C_2H^+_5 ion density in the plasma, which caused a reduction in higher hydrocarbon ions densities and, accordingly, in film deposition rate. The N^+_2 ion sputtering also plays a major role in a reduction of film deposition rate for relatively large RF powers. The incorporation of nitrogen atoms into the bonding network of the DLC film deposited was greatly suppressed at present gas pressure conditions.
Document Type: Regular Paper
Affiliations: Faculty of Engineering, Tokyo Denki University, 2-2 Kanda-Nishiki-cho, Chiyoda-ku, Tokyo 101, Japan
Publication date: 2001-06-01