Diagnostics of SiCOH-Film-Deposition in the Dielectric Barrier Discharge at Atmospheric Pressure

Abstract

The paper studies non‐thermal dielectric barrier discharges (DBD) operated in a parallel plate reactor (6 cm width and 16 cm long) under atmospheric pressure in Ar/HMDSO and Ar/HMDSO/O2 mixtures at different O2 to HMDSO ratio and different power. Emission spectroscopy and FT‐IR absorption spectroscopy were applied to get information on the reaction products in the DBD. The spectroscopic analysis was performed at three residence time. The properties of the polymer films deposited on silicon wafer were measured by FT‐IR absorption spectroscopy, AFM and XPS analysis. Surface tension was obtained from contact angle measurements with water and CJ2H2. The correlation between properties of plasma and the results of thin film diagnostics has been investigated.

Ar/HMDSO/O2 Fed Atmospheric Pressure DBDs: Thin Film Deposition and GC‐MS Investigation of By‐Products

“…FT‐IR spectra allow making some considerations on the HMDSO deposition mechanism in DBDs. In agreement with published data,7, 11, 14, 19, 24, 25, 30, 40, 41 without oxygen addition the deposit is mainly polydimethylsiloxane‐like with HMDSO structure retention; thus, as also confirmed by FT‐IR spectra, (CH 3 ) 3 SiOSi(CH 3 ) 2 , Si(CH 3 ) 3 , Si(CH 3 ) x O ( x = 2, 3, …) units could be considered representative of the main film precursors chemical structure. At high oxygen content in the feed a partial oxidation of these reactive fragments occurs.…”

“…Among the various experimental ways to generate non‐equilibrium plasmas at atmospheric pressure, dielectric barrier discharge (DBD) technology is one of the most popular approach for thin film deposition and in particular for the production of SiO x coatings (see, for instance, refs 11, 12, 28–43…”

“…Interesting results have also been published for atmospheric pressure cold plasmas containing HMDSO with the aim of correlating the plasma chemistry with the chemical composition and structure of the coating. Vinogradov et al40, 41 performed the FT‐IRAS and OES analysis of DBDs fed with Ar/HMDSO/O 2 and He/HMDSO/O 2 . In particular the investigation of the plasma phase with FT‐IRAS suggested that monomer fragmentation mainly results in the production of four radicals: (CH 3 ) 3 SiO, Si(CH 3 ) 3 , (CH 3 ) 3 SiOSi(CH 3 ) 2 , and CH 3 ; these reactive fragments can be responsible for the formation of pentamethyldisiloxane, trimethylsilane, and methane.…”

Film Deposition in the Dielectric Barrier Discharge at Atmospheric Pressure in He/O2/HMDSO and He/N2O/HMDSO mixtures

“…In a previous paper1, the film deposition processes at atmospheric pressure in dielectric barrier discharges (DBD) in Ar/HMDSO and Ar/O 2 /HMDSO mixtures were studied. Both, inorganic (SiO 2 ‐like) and polymer‐like films could be deposited in DBD.…”

“…Both, inorganic (SiO 2 ‐like) and polymer‐like films could be deposited in DBD. The direct analysis of the HMDSO dissociation products1–3 shows that the search for correlations between species produced in plasma and resulting thin film properties is a good way of finding out film deposition mechanisms. Mass spectrometry studies suggest a cracking of the SiO and the SiC bonds after electron impact 4, 5.…”