Adsorption of hydrocarbon components generated in deuterated benzene plasma studied by in situ real-time infrared absorption spectroscopy

Abstract

In situ, real-time infrared absorption spectroscopy in the multiple internal reflection geometry was employed to investigate the evolution of hydrocarbon components deposited during plasma-enhanced chemical vapor deposition with a deuterated benzene source. We detected a peak attributed to the C-D stretching vibration of the deuterated phenyl group, which indicated a mode in which the benzene ring structure is retained on the substrate during the adsorption. The evolution of each peak during the plasma exposure suggests that the addition reaction occurs during the adsorption. Furthermore, we observed that with increasing substrate bias applied, the benzene ring structures in the film were disrupted and the amount of alkane components increased. This addition reaction proceeded on the film surface, regardless of the substrate bias.

IR Absorption Spectroscopy of Deposition Process of Amorphous Carbon Film due to Ethylene Plasma

“…We observed broad peaks at 1600 to 1800 cm − 1 in the IR spectra. Based on the peak position, we believe the peak to be due to sp 2 -C. 10 This indicates that a chemical species that has C=C bonding was generated in the plasma and contributed to film formation. However, based on this spectra, we must consider sp 2 -C and sp 3 -CH X , the oscillator strength of each, and the influence of the angle on the detection sensitivity of each component.…”

“…This is the same as observed in cases of acetylene or benzene plasma. [10][11][12][13] Therefore, film deposition by ethylene plasma is not the result of a C=C or C≡C addition reaction but, rather, is the result of the abstraction of hydrogen and the adsorption of the chemical species generated in the plasma (the same as when methane is used). Furthermore, reasons why the ethylene deposition rate was less than two times the methane phase deposition rate include the adsorption coefficient of the radicals contributing to deposition possibly being smaller than that in the case of methane, and hydrogen having to be abstracted from the film twice.…”

Deposition of hydrophilic amorphous carbon film with ether as a source molecule and analysis of its deposition reaction

“…As illustrated in Figure , the PECVD chamber used in the experiment comprises an radio frequency (RF, 13.56 MHz) plasma source fabricated by winding a conductor around a glass tube, a vacuum exhaust system including a combination of a turbo molecule pump and a rotary pump, and a manipulator that sets the substrate . To enable in‐situ measurement of the reaction during deposition, an IR multiple internal reflection prism was used for the substrate.…”

“…One of the authors of this study, Prof. Shinohara, discovered that it is possible to deposit a film while maintaining the characteristics of the source material molecules when using benzene, acetylene, or a similar source material in PECVD . If we assume that the chemical bonding state of the source material molecules affects the deposited film, we can postulate that, since propyl groups have a sp 3 ‐ bonding form, fundamentally, a film having the same chemical bonding state as when methane molecules are used as the source material will be deposited.…”

Deposition of Hydrophilic Amorphous Carbon Film with Ether as a Source Molecule and Analysis of its Deposition Reaction

“…[5][6][7] If we assume that the chemical bonding state of the source material molecules affects the deposited film, we can postulate that, since propyl groups have a sp 3 -bonding form, fundamentally, a film having the same chemical bonding state as when methane molecules are used as the source material will be deposited. [5][6][7] If we assume that the chemical bonding state of the source material molecules affects the deposited film, we can postulate that, since propyl groups have a sp 3 -bonding form, fundamentally, a film having the same chemical bonding state as when methane molecules are used as the source material will be deposited.…”