Plasma-Enhanced CVD of Fluorocarbon Thin Films via CF3H/H2 Chemistries

Senkevich, Jay J.; Tutor, Michael J.; Sherrer, David W.

doi:10.1002/(sici)1521-3862(200002)6:1<13::aid-cvde13>3.0.co;2-2

Cited by 5 publications

(1 citation statement)

References 12 publications

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“…A trifluoromethane (CHF 3 ) plasma was used with the following parameters: CHF 3 flow rate = 50 sccm, CHF 3 pressure = 150 mTorr, Power = 180 W. The DC bias was recorded to be − 279 V. The thickness of the resulting fluoropolymer layer was measured to be 95 ± 2.2 nm, using a commercial precision surface profiler DektakXT (Bruker, USA), i.e. a deposition rate of ~ 25.3 ± 0.6 nm min -1 under these conditions—comparable with previous work 31 , 42 , 51 , 90 , 91 .…”

Section: Methodssupporting

confidence: 73%

Passivation of miniature microwave coplanar waveguides using a thin film fluoropolymer electret

Marzouk

Avramovic

Guérin

et al. 2021

Sci Rep

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The insertion losses of miniature gold/silicon-on-insulator (SOI) coplanar waveguides (CPW) are rendered low, stable, and light insensitive when covered with a thin film (95 nm) fluoropolymer deposited by a trifluoromethane (CHF3) plasma. Microwave characterization (0–50 GHz) of the CPWs indicates that the fluoropolymer stabilizes a hydrogen-passivated silicon surface between the CPW tracks. The hydrophobic nature of the fluoropolymer acts as a humidity barrier, meaning that the underlying intertrack silicon surfaces do not re-oxidize over time—something that is known to increase losses. In addition, the fluoropolymer thin film also renders the CPW insertion losses insensitive to illumination with white light (2400 lx)—something potentially advantageous when using optical microscopy observations during microwave measurements. Capacitance–voltage (CV) measurements of gold/fluoropolymer/silicon metal–insulator-semiconductor (MIS) capacitors indicate that the fluoropolymer is an electret—storing positive charge. The experimental results suggest that the stored positive charge in the fluoropolymer electret and charge trapping influence surface-associated losses in CPW—MIS device modelling supports this. Finally, and on a practical note, the thin fluoropolymer film is easily pierced by commercial microwave probes and does not adhere to them—facilitating the repeatable and reproducible characterization of microwave electronic circuitry passivated by thin fluoropolymer.

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