Vacuum Arc Ion Source Implantation Research Articles

Modification of anti-bacterial surface properties of textile polymers by vacuum arc ion source implantation

Abstract Ion implantation provides an important technology for the modification of material surface properties. The vacuum arc ion source is a unique instrument for the generation of intense beams of metal ions as well as gaseous ions, including mixed metal–gas beams with controllable metal:gas ion ratio. Here we describe our exploratory work on the application of vacuum arc ion source-generated ion beams for ion implantation into polymer textile materials for modification of their biological cell compatibility surface properties. We have investigated two specific aspects of cell compatibility: (i) enhancement of the antibacterial characteristics (we chose to use Staphylococcus aureus bacteria) of ion implanted polymer textile fabric, and (ii) the “inverse” concern of enhancement of neural cell growth rate (we chose Rat B-35 neuroblastoma cells) on ion implanted polymer textile. The results of both investigations were positive, with implantation-generated antibacterial efficiency factor up to about 90%, fully comparable to alternative conventional (non-implantation) approaches and with some potentially important advantages over the conventional approach; and with enhancement of neural cell growth rate of up to a factor of 3.5 when grown on suitably implanted polymer textile material.

Nonlinear refraction of lithium niobate crystal doped with different metal nanoparticles

The nonlinear optical refractive property of metal-implanted lithium niobate crystals has been investigated by using the Kerr-lens auto-correlation technique. The lithium niobate crystals fabricated by the Czochralski method were implanted with metal ions of Cu, Ag, Fe and Ni by using metal vapor vacuum arc ion source implanter. The magnitudes of the nonlinear refraction index of lithium niobate crystals have been improved by the metal ions implantation. The potentiation was analyzed from two aspects: the resonance interaction and the displacements in lithium niobate.

High concentration erbium doping of silicon-rich SiO 2 thin films on silicon

In this work, high concentration erbium doping in silicon-rich SiO 2 thin films is demonstrated. Si plus Er dual-implanted thermal SiO 2 thin films on Si substrates have been fabricated by using a new method, the metal vapor vacuum arc ion source implantation with relatively low ion energy, strong flux and very high dose. X-Ray photoelectron spectroscopy measurement shows that very high Er concentrations on the surfaces of the samples, corresponding to ∼10 at.% or the doping level of ∼10 21 atoms cm −3, are achieved. This value is much higher than that obtained by using other fabrication methods such as the high-energy ion implantation and molecular beam epitaxy. Reflective high-energy electron diffraction, atomic force microscopy and cross-section high-resolution transmission electron microscopy observations show that the excess Si atoms in SiO 2 matrix accumulate to form Si clusters and then crystallize gradually into Si nanoparticles embedded in SiO 2 films during dual-ion implantation followed by rapid thermal annealing. Er segregation and precipitates are not formed. Photoluminescence at the wavelength of 1.54 μm exhibits very weak temperature dependence due to the introduction of Si nanocrystals into the SiO 2 matrix. The 1.54-μm light emission signals from annealed samples decrease by less than a factor of 2 when the measuring temperature increases from 77 K to room temperature.

Study on the Dopedβ-FeSi 2 Obtained by Metal Vapor Vacuum Arc Ion Source Implantation and Post-Annealing

Abstractβ-FeSi2 was firstly formed by implanting Si wafers with Fe ions at 50 kV to a dose of 5×1017/cm2in a strong current Metal Vapor Vacuum Arc (MEVVA) implanter. Secondly, Ti implantation was performed on these Fe as-implanted samples. The Fe + Ti implanted samples were furnace annealed in vacuum at temperatures ranging from 650 to 975°C. The XRD patterns of the annealed samples correspond to β-FeSi2 structure (namely β-Fe(Ti)Si2). When annealing was done above 1050°C, the β-Fe(Ti)Si2 transformed into α-Fe(Ti)Si2. This implies that introducing Ti stabilizes the β-FeSi2 phase. Resistance measurements were also performed.

Low-temperature, direct synthesis of β-SiC by metal vapor vacuum arc ion source implantation

Crystalline β-SiC surface layers with strong (111) preferred orientation were synthesized by direct ion implantation into Si(111) substrates at a low temperature of 400°C using a metal vapor vacuum arc ion source. Both X-ray diffraction and Fourier transform infrared spectroscopy reveal an augment in the amount of β-SiC with increasing implantation doses at 400°C. Scanning electron microscopy shows the formation of an almost continuous SiC surface layer after implantation at 400°C with a dose of 7×10 17/cm 2. The full width at half maximum of the X-ray rocking curve of β-SiC(111) was measured to be 1.4° for the sample implanted at a dose of 2×10 17/cm 2 at 700°C, revealing a good alignment of β-SiC with the Si matrix.

The formation of Ti-silicides by a metal vapour vacuum arc ion source implantation and annealing process

Both 〈0 0 1〉 and 〈1 1 1〉 oriented Si wafers were implanted with Ti ions to 5×10 17ions/cm 2. Under various beam currents, X-ray diffraction (XRD) patterns show that there are different initial silicides created. The formation of C49 TiSi 2 and/or Ti 5Si 3 depends on beam currents and orientations of substrates. When larger beam current was used, C49 TiSi 2 and/or Ti 5Si 3 transformed into C54 TiSi 2. Therefore, the sheet resistance could be reduced. Anneals increase the phase transformation and the C54 TiSi 2 grows with preferential orientations. Different orientation relationships are found on two kinds of wafers. Moreover, it is noted that Ti atomic profile has only a small change after annealing.

Preferential growth of C54 TiSi 2 by metal vapor vacuum arc ion source implantation and post-annealing

Both 〈100〉 and 〈111〉 oriented Si wafers (n-type) were implanted with 45-keV Ti ions to a dose of 4×10 17 ions/cm 2. X-Ray diffraction (XRD) patterns show that there are different initial silicides, such as: C54 TiSi 2, C49 TiSi 2 and Ti 5Si 3. It is interesting that the initial phases are beam current and substrate dependent. When annealing was performed at higher temperature, both the C49 TiSi 2 and Ti 5Si 3 transform into C54 TiSi 2. Moreover, C54 TiSi 2 was grown with various preferential orientations on different substrates in annealing processes. Rutherford backscattering spectrometry (RBS) results show that the Ti atomic profile has little change through annealing. In addition, sheet resistance measurements also reflect that the synthesized disilicide is excellent in electrical conductivity. This suggests that the method has potential for realizing electrical contact in very large-scale integrated (VLSI) circuits.

The Growth and Thermal Stability of Ti-Silicides Obtained by Metal Vapor Vacuum Arc Ion Source Implantation

(100) and (111) oriented Si wafers were implanted with 45 keV, 5 x 10(17) cm(-2) Ti ions at various beam currents. X-ray diffraction (XRD) patterns show that there are different initial silicides such as C49 TiSi2 and Ti5Si3 on various wafers. While annealing was carried out at higher temperatures, both C49 TiSi2 and Ti5Si3 transform into C54 TiSi2. However, it is noted that C54 TiSi2 indicates different preferential orientations on two kinds of wafers. The change of sheet resistance with annealing temperature reflects that the disilicide is more stable than those obtained by solid phase reaction. It is also valuable to find that Ti atomic profiles show only small changes For various anneals.

Formation of Ti silicides by metal-vapor vacuum arc ion source implantation

Metal-vapor vacuum arc ion source was employed to synthesize Ti silicides by Ti implantation directly into Si or through a deposited titanium film on Si wafers. The implantation was conducted at room temperature at an extracted voltage of 40 kV. In the directly implanted Si wafers, the transition of Ti disilicides from a metastable C49-TiSi2 to an equilibrium phase C54-TiSi2 was observed when the current density was of 125 μA/cm2 at a nominal dose range of 3–5×1017/cm2, while in the Si wafers with a deposited Ti film, C54-TiSi2 was formed when the current density was of 125 μA/cm2 at a fixed nominal dose of 5×1017/cm2. The temperature rise caused by ion implantation was calculated by solving a differential thermal conduction equation and the results were employed to discuss the formation mechanism of Ti silicides.