Implant infection still represents a major clinical problem in orthopedic surgery. We therefore tested the in vitro biocompatibility and antibacterial effects of copper (Cu)- and silver (Ag)-ion implantation. Discs of a commonly used titanium alloy (Ti6AlV4) with an aluminium oxide-blasted surface were treated by Cu- or Ag-ion implantation with different dosage regimen (ranging from 1e15-17 ions cm(-2) at energies of 2-20 keV). The samples were seeded with primary human osteoblasts and cell attachment and proliferation was analyzed by an MTT-assay. In comparison to the reference titanium alloy there was no difference in the number of attached viable cells after two days. After seven days the number of viable cells was increased for Cu with 1e17 ions cm(-2) at 2 and 5 keV, and for Ag with 1e16 ions cm(-2) at 5 keV while it was reduced for the highest amount of Ag deposition (1e17 ions cm(-2) at 20 keV). Antibacterial effects on S.aureus and E.coli were marginal for the studied dosages of Cu but clearly present for Ag with 1e16 ions cm(-2) at 2 and 5 keV and 1e17 ions cm(-2) at 20 keV. These results indicate that Ag-ion implantation may be a promising methodological approach for antibacterial functionalization of titanium implants.

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Hard amorphous carbon (ta-C) films were implanted with 20 keV N+ ions with different fluences up to 6×1017/cm2 at different substrate temperatures. The nitrogen content of the films was monitored in situ using elastic recoil detection analysis. A characteristic temperature dependence is observed for the maximum achievable [N]/[C] composition ratio, with a drop of the saturation level from the room-temperature value of 0.35 to 0.17–0.12 above 150 °C. It is shown that the higher nitrogen retention at room temperature is correlated with the formation of N2-containing gas bubbles which are not present in samples implanted with high fluences at elevated temperatures. From residual-gas analyses it is found that nitrogen is reemitted from the films mainly as N2 when saturation occurs. Double-implantation experiments with spatially separated N14 and N15 implanted regions, respectively, indicate that the N–N molecule recombination observed at large implantation fluences occurs inside the films and not at the surface. Significant changes of the microstructure of the films are found with increasing implantation fluences. Inside the implanted near-surface region of several 10 nm thickness the density of the material decreases from 3.0 to about 1.7 g/cm−3. Graphitic clusters are identified in samples implanted up to saturation at 400 °C, using cross-section transmission electron microscopy. A basic approach to modeling the nitrogen saturation and release at large fluences is presented. Both nitrogen release and structural modification processes are interpreted as a tendency towards thermodynamic equilibrium which may constitute a strong driving force against the synthesis of nitrogen-rich hard C:N materials, compared to other nitride phases.

Cost reduction is the overall goal in the further development of solar cell technologies. Multicrystalline silicon has attracted considerable attention because of its high stability against light soaking. In case of solar grade mc-Si, the rigorous control of metal impurities is desirable for solar cell fabrication. Although ion implantation doping got very recently distinct consideration for doping of monocrystalline solar material, efficient doping of multicrystalline solar material remains the main challenge to reduce costs. The influence of different annealing techniques on the optical and electrical properties of mc-Si solar cells was investigated. Flash lamp annealing (FLA) in the ms-range is demonstrated here as a very promising technique for the emitter formation at an overall low thermal budget. It could be presented that FLA at 1000 °C for 3 ms even without preheating is sufficient to recrystallize implanted silicon. The sheet resistance of FLA samples shows the values of about 50 Ω/sq. Especially, the minority carrier diffusion length for the FLA samples is in the range of 80 μm without surface passivation. This is up to one order of magnitude higher than that observed from rapid thermal annealing or furnace annealing samples. This technology shows great promise to replace the conventional POCl3-doping.

The influence of photoresist pattern on charging damage of gate oxides during high current arsenic implantation is studied. Metal-oxide- semiconductor (MOS) capacitors of 10 mu m/sup 2/ active area and 4.5 nm oxide thickness connected with various types of poly antennas and resist patterns on top were processed, whereby the resist overlapped and/or enclosed the gate electrode during ion implantation. The evaluation of the devices was performed by leakage current and charge to breakdown (Qbd) measurements. The influence of resist size, perimeter, and coverage of polyelectrodes is described in detail