Effect Of Plasma Immersion Ion Implantation Research Articles

Optical properties of plasma‐treated PEEK: Monitoring colour and crystallinity for applications in medicine and dentistry using ellipsometry

AbstractPoly‐ether‐ether‐ketone (PEEK) is a widely used and versatile polymer. Here, we use ellipsometry to determine the wavelength‐dependent optical properties of PEEK before and after the surface is modified by plasma immersion ion implantation (PIII), a technique that renders the surface hydrophilic and bio‐active. Lorentz and Gaussian oscillator models are used to fit the data for extraction of the optical constants and the dielectric function. The effect of PIII, even for short treatment times, changes the optical properties of PEEK, indicative of an amorphisation of the initial semicrystalline structure that broadens the electronic density of states distribution. The progressive changes in the optical properties with treatment time allow assessment of colour changes and estimation of ion dose in the PIII process.

Plasma-polymerized acetylene nanofilms modified by nitrogen ion implantation

Thin films were prepared by plasma enhanced chemical vapour deposition (PECVD) from a mixture of acetylene and argon, and post deposition-treated by plasma immersion ion implantation (PIII). The effect of PIII on the nanofilms properties was evaluated as a function of treatment time. The average thickness and roughness were diminished upon PIII. On the other hand, hardness (0.7–3.9GPa) and elastic modulus (29–54GPa) increased upon 60min of ion bombardment. Such results are ascribed mainly to the densification of the film structure caused by the increment in the crosslinking degree with increasing the energy deposited in the films. Wettability of the samples, investigated by contact angle measurements, was reduced (from 64 to 21°) right after PIII. This result, attributed to the introduction of polar groups in the film structure, was not preserved as the sample was aged in atmosphere. After aging, contact angles were larger than 70° but still smaller than 90°. Although the wettability has decreased with aging, the hydrophilic character of the samples was preserved. For certain treatment times, nitrogen PIII turned the plasma-polymerized acetylene films smoother, denser, mechanically and tribologicaly more resistant than the as-deposited material.

Optimized AISI 304 steel nitriding in inductive RF N 2–H 2 plasmas

Optimal surface nitriding is closely related to plasma chemical composition. The effects of Plasma-Immersion Ion Implantation (PIII) nitriding with 15% N 2+85% H 2 type mixtures have been studied. A simplified PIII facility was assembled around an evacuated Pyrex cylindrical 500 mm long reactor with a 190 mm inner diameter, over which a 3.2 mm wide antenna was coaxially wound with a 240 mm inner diameter. The system was supplied by a 13.56 MHz RF generator whose electric component developed the plasma discharge. After the admission of the gas mixture to the reactor vessel the breakdown took place within 5–15 Pa work pressure and 450–500W RF power. The main plasma parameters were characterized including a 1.8 × 10 18 to 3.1 × 10 18 m −3 density by means of double Langmuir probes. An additional DC power supply was selected in order to bias AISI 304 stainless steel samples with a view to improving the steel hardness properties without compromising its corrosion resistance. The samples treated at different temperatures and for several periods, were evaluated by means of X-ray diffraction (XRD), which indicated the formation of nitrides, identified as Fe 3NiN and FeNiN and can be associated with the enhanced austenitic phase of the stainless steel. Scanning electron microscopy (SEM) assessed the atomic percentages of nitrogen both on the sample surface and through their cross-section. Vickers microhardness (HV) tests exhibited up to a 6–7 times increase at a 500g load. Finally, Raman spectroscopy studies established four active modes at 215, 267, 385 and 490 cm −1 with temperatures between 400 and 500 °C.

Multilayer structure, stress reduction and annealing of carbon film.

ABSTRACTCarbon films deposited by filtered cathodic arc show a high compressive stress which limits their thickness because of delamination. We study three methods of relieving the stress in these films. We first determine the dependence of the stress on DC bias up to bias voltages of 1200V and show that the formula of Davis provides a good fit to the data including the stress maximum in the region of 150–200V and the progressive decrease in stress at higher voltages. In the second method, plasma immersion ion implantation (PIII) was used to create multilayer of alternating high density, high stress (PIII on) films and lower density, low stress (PIII off) films. This method enabled thicker structures to be produced. In the third method we made multilayers using amorphous silicon and carbon layers. Annealing of these layers showed that the stress could be reduced to very low values because of the ability of the silicon layers to absorb compressive stress by contracting after the annealing step. The microstructural effects of PIII were studied by transmission and scanning electron microscopy.

Improve retained dose and impact energy of inner surface plasma immersion ion implantation using long pulse duration with deflecting electric field

Not restricted by the line-of-sight process, plasma immersion ion implantation (PIII) has shown great potential for inner surface modification, but the impact energy and retained dose turned to be very low. The process was investigated numerically and experimentally in this paper. The results show that a high percentage of low impact energy ions was the key factor that resulted in low impact energy on the inner surface. This was caused by sheath overlapping and appearance of the dead zone during inner surface PIII. Long pulse duration could alleviate this problem and increase ion impact energy on the inner surface, hence the implant depth, which was key factor for the modifying effect of PIII. Also, long pulse duration was helpful in improving the retained dose on the inner surface.

Thin film oxides as probe for homogeneity measurements of 3-dimensional objects treated by plasma immersion ion implantation

Results on an optical method are presented for investigation of the lateral homogeneity of treatment of 3-dimensional objects by plasma immersion ion implantation (PIII). It is based on interference colours of thin oxide films of transition metals such as titanium, niobium or tantalum. The thickness of the oxides and hence their colour changes when they are sputter etched by the plasma immersion ion bombardment. With the example of cube-shaped samples which are treated by argon PIII, it is demonstrated how this method works. Cube-shaped samples with slots with both inner and outer surfaces are a particularly interesting and illustrative example both for homogeneity effects of PIII and its measurement. It turns out that large differences in ion irradiation intensity between the outer parts and the inner parts of such samples develop. For the outer sides, a gradient in irradiation intensity is found. In contrast, the inner walls are hardly changed. However, by far most the inner bottom side of the samples is affected; it is considerably sputter etched. These unexpected results are explained by the shape of the cathode sheath from which the ions are accelerated and by the resulting ion trajectories.

Plasma immersion ion implantation for shallow junctions in silicon

Low cost and low voltage (<1 keV) Plasma Immersion Ion Implantation (PIII) for acceptor and donor doping was studied from RF plasmas of 1% PH 3–H 2 and 1% B 2H 6–H 2 and gas mixtures, respectively. Conventional annealing and Rapid Thermal Processing (RTP) were applied for the activation of the dopants forming junction depths in 0.1–0.215 μm range. The level of the co-implanted metal concentration was determined by Rutherford Backscattering Spectrometry and Deep Level Transient Spectroscopy (DLTS) technique and found lower than 1×10 11 ion/cm 3. The effects of PIII on the lifetime of carriers were followed by lifetime mapping. The lifetime degradation caused by PIII of medium duration was comparable with the effect of conventional doping processes.