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Physical feature exploration of nanocrystalline FeSi2 surface with argon plasma etching under varying power
(2023-12-01)
Borwornpornmetee, Nattakorn
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Sittimart, Phongsaphak
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Phatthanakun, Rungrueang
;
Nakajima, Hideki
;
Paosawatyanyong, Boonchoat
Nanocrystalline (NC) FeSi<inf>2</inf> films were created on Si(111) wafers via direct-current sputtering with facing targets at an ambient temperature, then the films were etched by Ar plasma generated through microwave source at different powers of 50, 100, and 150 W. The surface morphology of the as-coated NC FeSi<inf>2</inf> films showed numerous small uniform crystallites and root-mean-square roughness of 4.65 Å. The surface for each etched NC FeSi<inf>2</inf> film showed appearance of holes and slight increase in the roughness as the power increased. X-ray photoelectron spectra showed that the etching decreased the content of hydrophobic carbon and increased the presence of polar oxide group on the NC FeSi<inf>2</inf> films as the power increased. These changes should be the factor behind the shift from hydrophobic state to hydrophilic state. The contact angle of the unetched NC FeSi<inf>2</inf> film surface was 100.55°, which is hydrophobic. The NC FeSi<inf>2</inf> film's surface reached a minimum contact angle of 35.65°, which belong to hydrophilic state, when the etching power was increased to 150 W. The mechanical properties of NC FeSi<inf>2</inf> films rarely affect by Ar plasma. The change in surface state to nearly superhydrophilic after plasma etching indicate possibility to develop NC FeSi<inf>2</inf> into a self-cleaning surface coating material.
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Physical properties of fe3si films coated through facing targets sputtering after microwave plasma treatment
(2021-08-01)
Borwornpornmetee, Nattakorn
;
Charoenyuenyao, Peerasil
;
Chaleawpong, Rawiwan
;
Paosawatyanyong, Boonchoat
;
Phatthanakun, Rungrueang
Fe<inf>3</inf>Si films are deposited onto the Si(111) wafer using sputtering with parallel facing targets. Surface modification of the deposited Fe<inf>3</inf>Si film is conducted by using a microwave plasma treatment under an Ar atmosphere at different powers of 50, 100 and, 150 W. After the Ar plasma treatment, the crystallinity of the coated Fe<inf>3</inf>Si films is enhanced, in which the orientation peaks, including (220), (222), (400), and (422) of the Fe<inf>3</inf>Si are sharpened. The extinction rule suggests that the B<inf>2</inf>–Fe<inf>3</inf>Si crystallites are the film’s dominant composition. The stoichiometry of the Fe<inf>3</inf>Si surfaces is marginally changed after the treatment. An increase in microwave power damages the surface of the Fe<inf>3</inf>Si films, resulting in the generation of small pinholes. The roughness of the Fe<inf>3</inf>Si films after being treated at 150 W is insignificantly increased compared to the untreated films. The untreated Fe<inf>3</inf>Si films have a hydrophobic surface with an average contact angle of 101.70<sup>◦</sup> . After treatment at 150 W, it turns into a hydrophilic surface with an average contact angle of 67.05<sup>◦</sup> because of the reduction in the hydrophobic carbon group and the increase in the hydrophilic oxide group. The hardness of the untreated Fe<inf>3</inf>Si is ~9.39 GPa, which is kept at a similar level throughout each treatment power.
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Impact of annealing temperature and carbon doping on the wetting and surface morphology of semiconducting iron disilicide formed via radio frequency magnetron sputtering
(2020-09-01)
Charoenyuenyao, Peerasil
;
Promros, Nathaporn
;
Chaleawpong, Rawiwan
;
Borwornpornmetee, Nattakorn
;
Sittisart, Pattarapol
Iron disilicide (FeSi<inf>2</inf>) films were formed onto Si(111) substrates via radio-frequency magnetron sputtering at room temperature (RT) and 560 °C. The effects of annealing temperature and carbon (C) doping concentration on the physical properties of FeSi<inf>2</inf> films were investigated. For annealing conditions, the crystallinity of the unannealed FeSi<inf>2</inf> films was enhanced after annealing. The surface of unannealed FeSi<inf>2</inf> films consisted of many small crystallites, which were clustered after annealing at 500 °C. The root mean square roughness (R<inf>rms</inf>) of the unannealed FeSi<inf>2</inf> films increased from 0.94 nm to 5.32 nm after air-annealing at 500 °C. The surface of the unannealed FeSi<inf>2</inf> films exhibited an average contact angle (θ<inf>CA</inf>) of 102.35°, which decreased to 41.70° after annealing at 500 °C. For C-doping conditions, the X-ray diffraction patterns for the undoped and C-doped FeSi<inf>2</inf> revealed β(202/220) and β(404/440) peaks. The undoped FeSi<inf>2</inf> film surfaces presented many small grains with grain boundaries, where the C-doped FeSi<inf>2</inf> films displayed a finer surface. R<inf>rms</inf> of the undoped FeSi<inf>2</inf> film surface was 15.71 nm, which decreased to 10.59 nm for 3.0 at.% C-doped FeSi<inf>2</inf> films. The average θ<inf>CA</inf> of the undoped FeSi<inf>2</inf> films was 108.35°, and this reduced slightly to 103.65° for 3.0 at.% C-doped films. Based on the obtained results, it was shown that the as-formed FeSi<inf>2</inf> and FeSi<inf>2</inf> films after annealing at 100 and 300 °C formed at T<inf>sub</inf> of RT, together with the undoped and C-doped FeSi<inf>2</inf> films formed at T<inf>sub</inf> of 560 °C, could potentially be employed for hydrophobic coating applications.

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