Structures and properties of fluorinated amorphous carbon films

Abstract

Fluorinated amorphous carbon (a-C:F) films were deposited by radio frequency bias assisted microwave plasma electron cyclotron resonance chemical vapor deposition with tetrafluoromethane (CF4) and acetylene (C2H2) as precursors. The deposition process was performed at two flow ratios R=0.90 and R=0.97, where R=CF4/(CF4+C2H2). The samples were annealed at 300 °C for 30 min. in a N2 atmosphere. Both Fourier transform infrared and electron spectroscopy for chemical analyzer were used to characterize the a-C:F film chemical bond and fluorine concentration, respectively. A high resolution electron energy loss spectrometer was applied to detect the electronic structure. The higher CF4 flow ratio (R=0.97) produced more sp3 linear structure, and it made the a-C:F film smoother and softer. A lifetime of around 0.34 μs and an energy gap of ∼2.75 eV were observed in both the as-deposited and after annealing conditions. The short carriers lifetime in the a-C:F film made the photoluminescence peak blueshift. The annealing changed both the structure and composition of the a-C:F film. The type of fluorocarbon bond and electronic structure characterized the mechanical and physical properties of a-C:F film.

Effect of UV Irradiation on Modification and Subsequent Wet Removal of Model and Post-Etch Fluorocarbon Residues

“…This broad absorption band suggests that the deposited polymer is not composed of only CF 2 , which is characterized by a well-resolved doublet at 1160 and 1220 cm −121-24 but rather it consists of a complex structure including different CFx groups. The absorption band at ∼1730 cm −1 can be assigned to terminal double bonds in the form of -CF = CF 2 20,21,24 and also C = O groups.…”

Surface stability and electronic structure of hydrogen- and fluorine-terminated diamond surfaces: A first-principles investigation

“…[11][12][13]19 It was also reported that an increase in the fluorine concentration of DLC films caused the formation of -CF, -CF 2 , and -CF 3 groups, which in turn reduced the surface energy. 10,11,13,15,34,39,40 It has been proposed that fluorine hinders interactions between surface carbon atoms and the environment more effectively than hydrogen, resulting in a more chemically stable surface for DLC coatings, because of its size, which is larger than H. The formation of fluorocarbons was also reported to break the cross-linked diamond structure 19,35 and enhance sp 3 bonding, 11,14 suggesting that a higher F content would weaken the film's hardness.…”

“…9 Studies showed that the incorporation of fluorine caused an increase in the water contact angle, hence a decrease in surface energy, proportional to the fluorine content. [10][11][12][13][14][15][16][17][18] In contrast, an increase in fluorine concentration decreased film hardness, with the resulting hardness values much lower than hydrogenated DLC films. 11,14,19 Tribological properties of films were reported to have optimum values for moderately [0.1< [F/(F þ C)] < 0.2] fluorinated films, 5 which was evidenced by sliding experiments.…”

“…[10][11][12][13][14][15][16][17][18] In contrast, an increase in fluorine concentration decreased film hardness, with the resulting hardness values much lower than hydrogenated DLC films. 11,14,19 Tribological properties of films were reported to have optimum values for moderately [0.1< [F/(F þ C)] < 0.2] fluorinated films, 5 which was evidenced by sliding experiments. 11,20 Meanwhile, atomic force microscopy (AFM) showed that both adhesive force and COF decreased with an increase in fluorine concentration.…”

UV-Assisted Modification and Removal Mechanism of a Fluorocarbon Polymer Film on Low-k Dielectric Trench Structure

“…Various plasma-polymerized fluorocarbon films were also found to have significant absorption in the >230 nm range attributed to the active chromophores within. [18][19][20][21] We propose that the carbonyl chromophore, instead of olefins and C-O proposed previously by Le et. al.…”