Metal Vapor Vacuum Arc Implantation Research Articles

Synthesis of Ag ion-implanted TiO2 thin films for antibacterial application and photocatalytic performance

TiO2 thin films were deposited by spin coating method. Silver ions were implanted into the films using a Metal Vapor Vacuum Arc implanter. The antibacterial ability of implanted films was tested using Escherichia coli removal under fluorescent irradiation and in the dark. The concentration of E. coli was evaluated by plating technique. The photocatalytic efficiency of the implanted films was studied by degradation of methyl orange under fluorescent illumination. The surface free energy of the implanted TiO2 films was calculated by contact angle testing. Vitamin C was used as radical scavengers to explore the antibacterial mechanism of the films. The results supported the model that both generation of reactive oxygen species and release of silver ions played critical roles in the toxic effect of implanted films against E. coli. XPS experimental results demonstrated that a portion of the Ag(Ag3+) ions were doped into the crystalline lattice of TiO2. As demonstrated by density functional theory calculations, the impurity energy level of subtitutional Ag was responsible for enhanced absorption of visible light. Ag ion-implanted TiO2 films with excellent antibacterial efficiency against bacteria and decomposed ability against organic pollutants could be potent bactericidal surface in moist environment.

Study of antibacterial, hydrophilic and nanomechanical properties of TiOX films modified by Ag+ beam implantation

TiOx thin films were deposited on glass substrates by electron-beam evaporation system using TiO2 as a source material. Silver ions were implanted with metal vapor vacuum arc implanter at 40kV. The dose of implanted ions was chosen as 1×1015, 3×1015, 6×1015, 9×1015 and 1×1016ions/cm2. The antibacterial property of Ag-TiOx films was tested using E. coli removal under UV light exposure, and E. coli concentration was evaluated by plating technique. The hydrophilic property was performed by water contact angle with contact angle meter. A nano-indentation instrument was used for nanomechanical tests. XPS was chosen to characterize the modified films. The results showed that the antibacterial, hydrophilic and nanomechanical properties of Ag–TiOx films were improved. The dose of implanted ions for the film with best antibacterial and hydrophilic abilities was 9×1015ions/cm2. The hardness and modulus of the films increased as the dose of implanted ions increased.

Influence of V+-implantation on structural, chemical, optical and nanomechanical properties of TiO2 films

TiO2 thin films were deposited by sol-gel method. V+ ions were implanted by using metal vapor vacuum arc implanter at 40 kV. The dose of implanted V+ ions was chosen as 6 × 1015, 1 × 1016, 3 × 1016 and 6 × 1016 ions/cm2. The investigations of structural, optical, nanomechanical and chemical characterizations of implanted thin films were carried out. The grain size of as deposited TiO2 film was about 23 nm, and the size was reduced after implantation. Implantation had no influence on the lattice parameters “a” and “c” of the films. Band gap of as deposited TiO2 film was estimated as 3.45 eV. The band gap of implanted films was found to decrease with increasing the dose of implanted ions. The refractive index of the implanted films increased with increasing the dose of implanted ions.

Preparation and Photocurrent Performance of Highly Ordered Titania Nanotube Implanted with Ag/Cu Metal Ions

Ag/Cu-doped titania nanotubes (Ag/TiNT, Cu/TiNT) are prepared by a metal vapor vacuum arc implanter. A scanning electronic microscope is employed for microstructural characterization. The photo-current performance of doped titania nanotubes under UV and visible light is tested by an electrochemical workstation CS300UA, the results show that the absorption edge of both Ag/TiNT and Cu/TiNT samples shifts to the visible light region and the band gap becomes narrower. Ag/TiNT possesses better photo-current ability than Cu/TiNT under UV and visible light. Titania doped with Ag and Cu metal ions is also studied based on the linearized augmented plane-wave method implemented by WIEN2k package, the result becomes better with the experimental performance.

Analysis of surface morphological change in PET films induced by tungsten ion implantation

Surface morphological changes and metal nanograin formation of polyethylene terephthalate films with tungsten ion implantation were studied. Tungsten ions were accelerated with a voltage of 40 kV and implanted at fluences from 5 × 10 16 to 2 × 10 17 cm −2 using a metal vapor vacuum arc implanter. Scanning electron micrographs at the highest fluence show semi-spherical hills, indicating formation of tungsten nanograins on the polymer. The tungsten nanograin formation in the polymer film is confirmed by cross-sectional observation using transmission electron microscopy. Depth profiles of tungsten atoms obtained from energy dispersive X-ray spectra indicate densification and sputtering of the polymer surface layer during implantation. These results indicate that surface morphological change is related with the effects of a critical fluence and tungsten nanograin formation.

Study on the Properties of TiN Coatings on Previously Ion-Implanted Pure Magnesium Surface by MEVVA Ion Implantation

A metal vapor vacuum arc (MEVVA) is used in ion implantation for substrate preparation before the deposition process which would ensure the improvement of mechanical properties of the coating. Ti ion is implanted into pure magnesium surface by MEVVA implanter operated with a modified cathode. Implanting energy is kept at 45 keV and dose is set at 3 × 1017 cm-2. TiN coatings are deposited by magnetically filtered vacuum-arc plasma source on unimplanted and previously implanted substrates. Microstructure and phase composition are analysed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The property of corrosion resistance of TiN coatings was studied by CS300P electrochemistry-corrosion workstation, and the main impact factor of the corrosion resistance was also analyzed.

Spiral patterns of gold nanoclusters in silicon (100) produced by metal vapour vacuum arcimplantation of gold ions

Self-assembled gold nanoclusters are attractive building blocks for future nanoscale sensorsand optical devices due to their exciting catalytic properties. In this work, we report directbottom-up synthesis of spiral patterns of gold nanoclusters in silicon (100) substrates byAu ion implantation followed by thermal annealing. This unique phenomenon is observedonly above a critical threshold implantation dose and annealing temperature.Systematic study by electron microscopy, analytical x-ray diffraction and atomicforce microscopy shows the temperature- and time-dependent nucleation, growthof Au nanoclusters and evolution of the spiral patterns. The observed patternsof gold nanoclusters bear a resemblance to the spiral growth prevalent in somedirectionally solidified eutectic alloys. Based on this systematic study of the growth andmorphology of nanoclusters, a tentative model has been proposed for the formationmechanism of this unusual self-assembled pattern in an amorphous Si/Au system. Thismodel shows that melting of the implanted layer is essential and without whichno spiral patterns are observed. A better understanding of this self-assemblyprocess will open up new ways to fabricate ordered arrays of gold nanoclusters insilicon substrates for seeding selective growth of one-dimensional nanostructures.

Tribological property enhancement of CrN films by metal vapor vacuum arc implantation of Vanadium and Carbon ions

CrN films have been extensively used in precision forming and molding applications because of their excellent tribological properties and oxidation-resisting characteristics. Vanadium and carbon ions are introduced into the near surface layer of deposited CrN films via metal vapor vacuum arc implantation to improve the wear performance of CrN films. Dense and smooth CrN film was deposited using a filtered arc deposition system, which provides fully ionized Cr plasma on the substrate surface. Subsequently, surface bombardment of the deposited CrN film with vanadium and carbon ions densifies the film and forms an alloy near the surface. These CrN-based films were characterized by X-ray photoelectron electron and Auger electron spectroscopies. Examinations of the tribological and mechanical film properties, including wear resistance, corrosion resistance and fracture toughness were performed and correlated with respect to the implantation parameters.

Study on the Properties of Alumina Ceramics after Implanted by Titanium Ions with MEVVA Sources

HIP (hot isostatic pressed) high-purity alumina was modified by Ti-ion implantation in a MEVVA (Metal Vapor Vacuum Arc) implanter. The samples were implanted by Ti ions with nominal doses 5×1016 to 1×1018 ions/cm2 under ambient temperature. The effects of titanium implantation and the ion dose implanted on the microstructures and mechanical properties of the ceramics were studied. After implanted by Ti ions, the maximum nanohardness of the as-implanted ceramics were increased about 20%; the bending strength were increased about 22%; the life of the alumina cutting tools were about 2 times longer than before. The result showed that all the factors of the improvement of the ceramic surface states played an important role on the mechanical properties after implantation.

Photoluminescence and electroluminescence properties of FeSi2-Si structures formed by MEVVA implantation

AbstractWe have prepared FeSi2 precipitates of nanometer size in Si by ion implantation using a metal vapor vacuum arc (MEVVA) ion source and studied their photoluminescence properties. Broad photoluminescence (PL) spectra at around 1550 nm were observed for all samples attributed to emission from the FeSi2 precipitates. It was found that all the PL spectra can be decomposed into two peaks, a main peak at near 1530 nm and a satellite peak at 1607 nm. Samples with a furnace annealing (FA) step at a lower temperature of 850°C are found to have a main peak position at a longer wavelength close to 1540 nm. For samples with a FA step at higher temperatures, the main peak position shifts to shorter wavelengths of near 1525 nm. In addition, we have also prepared MOS structures with implanted FeSi2 precipitates incorporated in the structures and measured their EL properties. The EL properties from these FeSi2-Si MOS structures after various thermal treatments were measured as a function of temperature from 80 to 300 K. Our preliminary results show that clear EL signals are obtained even at room temperature under appropriate processing conditions.

An upper limit of concentration for erbium photoluminescence from silica-based thin films formed by MEVVA implantation

SiO 2 thin films containing nanocrystalline Si (nc-Si) and Er ions have been fabricated by using a metal vapor vacuum arc (MEVVA) ion source. Photoluminescence (PL) properties of the films were studied as the function of the Er ion dose. The PL intensity was found to be strongly enhanced by incorporating nc-Si in the films. The intensity of the 1.54 μm luminescence peaks firstly increases with the increasing of the Er concentration, arriving at a maximum with Er concentration of 8.0 at.% at room temperature (RT). Then PL yields decreased with further increase in Er ion dose. A mechanism about energy transferring between the photogenerated carrier in the nc-Si and Er 3+ in SiO 2 has been investigated.

Effects of substrate temperature and annealing temperature on the formation and properties of erbium silicide layers synthesized by high current Er ion implantation

Ion beam synthesis of ErSi2−x by erbium implantation into Si wafers with a metal vapor vacuum arc (MEVVA) ion source has been performed and the effects of substrate temperature and annealing temperature on its properties have been investigated. The implantation was performed at an extraction voltage of 60 kV to ion doses ranging from 5×1016 to 2×1017 cm−2 with beam current densities from 3 to 26 μA/cm2 corresponding to substrate temperatures ranging from 85 to 245 °C. The characterization of the as-implanted and annealed samples was performed using Rutherford backscattering spectrometry, x-ray diffraction, atomic force microscopy, and electrical resistivity measurements. The results showed that ErSi2−x phase was directly formed by MEVVA implantation when the substrate temperature Ts⩾200 °C. For the samples synthesized at lower implantation temperatures, postimplantation annealing is necessary to achieve the formation of ErSi2−x. Direct measurements of the sputtering depth on masked implanted samples at various substrate temperatures showed that the sputtering yield increases with increasing temperature. The intensive sputtering and aggregation due to high substrate temperatures result in surface fractal patterns, in some cases, discontinuous layers, thus the high resistivity of the layers.

XTEM characterization of tungsten implanted SiC thin films on silicon for field emission devices

Nanocrystalline surface layers of WC and SiC are formed by a sequential high-dose metal vapour vacuum arc implantation of carbon and tungsten ions into Si(1 0 0) and subsequent rapid thermal annealing. These layer systems are shown to provide electron field emitter structures with turn-on-fields as low as 15–20 V/μm. The formation of carbide and silicide phases as well as that of cavities at the SiC/Si–substrate interface upon annealing are discussed on the basis of X-ray diffraction, X-ray photo electron spectroscopy, cross-section transmission electron microscopy and HREM measurements.

Optimum silicon ion dose for 1540 nm photoluminescence from erbium-doped silica thin films formed by MEVVA implantation

In this work, SiO 2 thin films containing Er and Si nanocrystals were prepared by implantation with a metal vapor vacuum arc (MEVVA) ion source. Photoluminescence (PL) properties of the films at 77 K and at room temperature (RT) were studied as functions of the Si ion dose. The PL intensities were strongly enhanced by the incorporation of nanocrystalline Si (nc-Si) in the SiO 2 films. The intensity of the 1.54 μm luminescence peak first increased with increasing Si dose, arriving at a maximum at a Si dose of 5×10 17 cm −2, then decreased with further increase in Si dose. These results are discussed and understood in terms of the role of nc-Si in Er luminescence mechanisms in silica containing nc-Si.

Ion beam synthesis and characterization of yttrium silicide

Abstract Buried hexagonal AlB2-type YSi2 layers were formed by metal vapor vacuum arc implantation of 100 keV yttrium ions to a dose of 1×10 18 Y + cm −2 into p-type Si (1 1 1) wafers. The heterostructures were analyzed by X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), Fourier transform infrared (FTIR) transmittance spectroscopy and the four-point probe technique. The results of XRD and RBS showed that YSi2 was formed directly during the implantation, and the implanted region from the surface to the interior of the Si substrate could be divided into four layers based on the concentration profile. The preferred growth was observed after infrared radiation. In situ measurements of sheet resistance during infrared irradiation showed that the as-implanted sample is metastable and the stable structure can be formed after irradiation at 530°C. Characteristic phonon bands of YSi2−x silicides have been observed by FTIR spectroscopy.

The effects of MEVVA ion implantation on the tribological properties of PVD-TiN films deposited on steel substrates

The effects of post-deposition metal vapour vacuum arc (MEVVA) ion implantation into TiN films were studied as part of a continuous effort to improve the wear performance of coatings used for cutting tools. This is a first account on the tribological behaviour of PVD-TiN coatings deposited on steel substrates and treated by MEVVA ion implantation. Two types of species were selected, C and W, one light and one heavy. In all cases, after implantation, tribological improvements were observed: The friction coefficient of the PVD-TiN against ruby was significantly reduced from 0.75 to 0.18 with carbon implantation at a dose of 10 17 cm −2 and the lifetime to spalling was improved by more than 200%. (Untreated films detached after approx. 5000 cycles, whereas implanted films were still well adhered after 19 000 cycles.) For C-implanted samples, an increase in nano-hardness in the near surface region was also observed. These effects are attributed to the formation of a carbonaceous layer on the surface, accompanied by the formation of TiC in the sub-surface region, as detected by XRD. In contrast, W implantation improved coating wear life, but not friction coefficient or nano-hardness. The results are compared to those obtained for MEVVA implantation into CVD-TiN and to conventional implantation.

Annealing behaviour of foreign atom incorporated Co-silicides formed by MEVVA implantation into SiO 2/Si and Si 3N 4/Si structures

Si 3 N 4/ Si(1 0 0), SiO 2/ Si(1 0 0) and SiO 2/ Si(1 1 1) wafers were implanted by keV Co ions under technical conditions to form thin silicide surface films. A metal vapour vacuum arc (MEVVA) source was employed to produce a high fluence of Co ions that was just sufficient to remove the oxide/nitride overlayer by sputter erosion. This high-fluence implantation under technical vacuum introduces foreign atoms into the implanted layer. The behaviour of these impurities following ∼900°C heat treatment in a N 2 atmosphere has been studied. Elemental redistributions, crystal recovery, phase formation and electric properties were analysed. The results show that the annealing leads to an increase in crystal ordering within the implanted layer and stable phase formation, as indicated by a reduction in the channeling signal and a decrease in electrical resistivity. In the case of nitride-coated samples, the heat treatment leads to a reduction in the residual carbon and nitrogen in the samples, while the oxygen content is largely unchanged. In contrast, a remarkable increase in the carbon and especially the oxygen contents is observed in the case of the samples with oxide overlayers, and the Co shows a tendency to spread to greater depths.

Sputtering transients for some transition elements during high-fluence MEVVA implantation of Si

The approach to quasi equilibrium sputtering of transition elements Co, Er, V and Ni during high-fluence implantation of Si(1 1 1) using a metal vapour vacuum arc (MEVVA) source has been studied by time of flight-energy elastic recoil detection analysis (ToF-E ERDA) and scanning electron microscopy (SEM). The partial sputter yield of the implanted species was determined from the change in the content of the implanted species with the implanted ion fluence. The partial sputter yield of Co exhibits a step-like rise to ∼0.4 that might be associated with a rapid segregation of Co to the surface followed by a slow exponential-like increase. Er on the other hand follows an exponential approach to the quasi-equilibrium partial sputtering yield which is indicative of no strong buildup of Er within the sputter escape depth. Additional data for Ni and V suggest also an exponential approach to quasi-equilibrium sputtering.

Spectroscopic ellipsometry studies of buried CoSi 2 layers in Si formed by ion implantation with a metal vapor vacuum arc ion source

Co ion implantation into Si substrate with a metal vapor vacuum arc (MEVVA) ion source has been studied by spectroscopic ellipsometry (SE) over the wavelength range of 400–2000 nm. A series of samples synthesized at different substrate temperatures during implantation ( T S ) and then post-annealed at the same conditions have been investigated. SE studies show that the buried CoSi 2 layer shifts towards the surface and the surface roughness becomes thicker as T S increases. Studies also show that, using MEVVA implantation, buried CoSi 2 layers can be formed at relatively low T S and relatively low annealing temperature. However, higher temperature annealing is essential for elimination of the damage in the top Si layer and formation of sharp interface.

Very low resistance CoSi 2 formation by metal vapour vacuum arc implantation into SiO 2/Si and Si 3N 4/Si structures

A metal vapour vacuum arc (MEVVA) implanter was used to form very low sheet resistance silicide CoSi 2 in the structures of SiO 2/Si and Si 3N 4/Si. Prior to Co implantation, wafers of Si (100) and Si (111) were covered with SiO 2 and Si 3N 4 films to form SiO 2/Si and Si 3N 4/Si structures. The metal ions of Co were implanted into Si, SiO 2/Si and Si 3N 4/Si structures at an energy of 40 keV and doses of (0.5–1.0)×10 18/cm 2. After Co implantation, the samples were annealed at 800–950°C for 10–30 s in ambient N 2. The sheet resistance R □ was measured for each samples before and after annealing. The R □ was 10–60 Ω/□ before annealing and 0.4–9.0 Ω/□ after annealing. Excellent silicide CoSi 2 films with very low sheet resistance R □<0.5 Ω/□ were obtained on the SiO 2/Si and Si 3N 4/Si structures. The sheet resistance R □ of CoSi 2 using the SiO 2/Si and Si 3N 4/Si structures is less than one to two orders than the R □ of CoSi 2 using the Si wafers directly. The excellent silicide CoSi 2 films with very low resistivity have a great advantage for use in VLSI-CMOS technology. Time-of-flight energy elastic recoil detection (ToF-EERD) analysis was used to measure the depth distributions of O, N, Co and Si. The SiO 2 and Si 3N 4 films were almost sputtered away after Co implantation into SiO 2/Si and Si 3N 4/Si structured wafers. The ERD results proved that these sacrificial films of oxide or nitride as protective films can be used to reduce sputter erosion and roughening in high dose metal implantation of silicon, resulting in excellent electrical properties.