Laser desorption/ionization fourier transform mass spectrometry of thin films deposited on silicon by plasma polymerization of acetylene

Abstract

Thin films deposited on silicon substrate by three different methods of plasma polymerization of acetylene were analyzed by direct laser desorption/ionization Fourier transform mass spectrometry. High-resolution mass spectra showed the presence of carbon clusters and hydrocarbon oligomers in different relative abundances. During unipolar and continuous discharge polymerization of acetylene-hydrogen gas mixtures, quadrupole mass spectra of the plasma constituents showed the presence of molecular species with m/z lower than 100 -mainly peaks of C 4 H 2 and C 6 H 2 . Films produced had smooth surfaces and the corresponding LDI-FTMS spectra displayed only carbon cluster signals in the positive ion mode and both hydrocarbon and carbon cluster signals (with much higher relative abundance of carbon cluster signals) in the negative ion mode. Alternatively, during bipolar discharge with either higher acetylene gas flux (Ͼ40 cm 3 /min) or longer deposition times (Ͼ10 min), quadrupole mass spectra of the plasma constituents showed signals corresponding to polycyclic aromatic hydrocarbons (PAH) with m/z higher than 100. SEM pictures of the bipolar thin films demonstrated the presence of "flower" structures and nanoparticles developed on the surface. LDI-FTMS spectra of such thin films showed either total absence or lower relative abundance of carbon cluster signals, compared with hydrocarbon signals. (J Am Soc Mass Spectrom 2010, 21, 411-420)

Structural Characterization of γ‐Terpinene Thin Films Using Mass Spectroscopy and X‐Ray Photoelectron Spectroscopy

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Investigation of the Growth Mechanisms of a-CHx Coatings Deposited by Pulsed Reactive Magnetron Sputtering

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