Studies of bone cell adhesion and proliferation on ion implanted titanium discs

Argon ions were implanted on titanium discs to study its effect on bone cell adhesion and proli feration. Polished titanium discs were prepared and implanted with argon ions with different doses. Afterwards the samples were sterilized using UV light, inocu lated with human bone cells and incubated. Once fixed and rinsed, image analysis has been used to quantify the number of cells attached to the titanium discs. Cell proliferation tests were also conducted after a period of 120 hours. Cell adhesion was seen to be higher with ion im planted surface. SEM analysis has shown that the cells attached spread more on ion implanted surface. The numbers of cells attached were seen to be higher on implanted surfaces; they tend to occupy wider areas with healthier cells.

RESIDUAL DEFECTS FOLLOWING RAPID ANNEALING OF BORON IMPLANTED SILICON WITH AND WITHOUT PREAMORPHISATION BY SILICON IMPLANTATION.

Implants of boron into silicon which has been made amorphous by silicon implantation have a shallower depth profile than the same implants into silicon. This results in higher activation and restricted diffusion of the B implants after annealing, and there are also significant differences in the microstructure after annealing compared with B implants into silicon. Rapid isothermal heating with an electron beam and furnace treatments are used to characterize the defect structure as a function of time and temperature. Defects are seen to influence the diffusion of non-substitutional boron.

TRANSIENT SCANNING ELECTRON BEAM ANNEALING METHODS USED TO STUDY DIFFUSION AND DEFECTS IN IMPLANTED SILICON.

Rapid thermal annealing of arsenic and boron difluoride implants, such as those used for source/drain regions in CMOS, has been carried out using a scanning electron beam annealer, as part of a study of transient diffusion effects. Three types of e-beam anneal have been performed, with peak temperatures in the range 900 -1200 degree C; the normal isothermal e-beam anneals, together with sub-second fast anneals and 'dual-pulse' anneals, in which the sample undergoes an isothermal pre-anneal followed by rapid heating to the required anneal temperature is less than 0. 5s. The diffusion occuring during these anneal cycles has been modelled using SPS-1D, an implant and diffusion modelling program developed by one of the authors. This has been modified to incorporate simulated temperature vs. time cycles for the anneals. Results are presented applying the usual equilibrium clustering model, a transient point-defect enhancement to the diffusivity proposed recently by Fair and a new dynamic clustering model for arsenic. Good agreement with SIMS measurements is obtained using the dynamic clustering model, without recourse to a transient defect model.

Strong visible and infrared photoluminescence from Er-implanted silicon nitride films

Silicon nitride films were deposited by plasma-enhanced chemical-vapour deposition. The films were then implanted with erbium ions to a concentration of 8 x 10(20) cm(-3). After high temperature annealing, strong visible and infrared photoluminescence (PL) was observed. The visible PL consists mainly of two peaks located at 660 and 750 nm, which are considered to originate from silicon nanocluster (Si-NCs) and Si-NC/SiNx interface states. Raman spectra and HRTEM measurements have been performed to confirm the existence of Si-NCs. The implanted erbium ions are possibly activated by an energy transfer process, leading to a strong 1.54 mu m PL.

Passive Q-switched mode locking of double-clading Yb : fiber laser with ion-implanted GaAs

We report the technique of the ion-implanted semi-insulating GaAs wafer used for passive Q-switched mode locking in double-cladding Yb:fiber laser. The wafer was implanted with 400-keV energy, 10(16)/cm(2) dose As+ ions, and was annealed at 600degreesC for 20 min. At the pump power of 5W, we achieved output power of 200mW. The repetition rate of envelope of Q-switched mode locking is 50-kHz with a FWHM envelope of 4mus. The repetition rate of mode locked pulse train was found to be 15-MHz. This is the first report of such a kind of laser to the best of our knowledge.

Enhanced near-infrared photoluminescence from isoelectronic luminescent centers in sulfur-implanted silicon with copper or silver coimplantation

Enhanced near-infrared photoluminescence (PL) from sulfur-related isoelectronic luminescent centers in silicon was observed from thermally quenched sulfur-implanted silicon in which additional copper or silver ions had been coimplanted. The PL from the sulfur and copper coimplanted silicon peaked between 70 and 100 K and persisted to 260 K. This result strongly supports the original conjecture from the optical detection of magnetic resonance studies that the strong PL from sulfur-doped silicon comes from S-Cu isoelectronic complexes [Frens , Phys. Rev. B 46, 12316 (1992); Mason , ibid. 58, 7007 (1998).]. (c) 2007 American Institute of Physics.

Bioactivity of Mg-ion-implanted zirconia and titanium

Titanium and zirconia are bioinert materials lacking bioactivity. In this work, surface modification of the two typical biomaterials is conducted by Mg-ion-implantation using a MEVVA ion source in an attempt to increase their bioactivity. Mg ions were implanted into zirconia and titanium with fluences ranging from 1 x 10(17) to 3 x 10(17) ions/cm(2) at 40 keV. The Mg-implanted samples, as well as control (unimplanted) samples, were immersed in SBF for 7 days and then removed to identify the presence of calcium and phosphate (Ca-P) coatings and to characterize their morphology and structure by SEM, XRD, and FT-IR. SEM observations confirm that globular aggregates are formed on the surfaces of the Mg-implanted zirconia and titanium while no precipitates are observed on the control samples. XRD and FT-IR analyses reveal that the deposits are carbonated hydroxyapatite (HAp). Our experimental results demonstrate that Mg-implantation improves the bioactivity of zirconia and titanium. Further, it is found that the degree of bioactivity is adjustable by the ion dose. Mechanisms are proposed to interpret the improvement of bioactivity as a result of Mg implantation and the difference in bioactivity between zirconia and titanium. (c) 2006 Elsevier B.V. All rights reserved.

The micro-magnetic structures of Mn+ ion-implanted GaSb

The micro-magnetic structures of Mn+ ion-implanted GaSb are studied using a magnetic force microscope (MFM). MFM images reveal that there are many magnetic domains with different magnetization directions in our samples. The magnetic domain structures and the magnetization direction of typical MFM patterns are analyzed by numeric simulation.

Stress corrosion studies of ion implanted austenitic steel

Stress corrosion studies of 50 Mn18Cr4 austenitic steel implanted with 120 keV N+, 100 keV Cr+, 200 keV and 400 keV Er+ ions were carried out by constant strain method in the nitrate solution. Surface composition and depth profiles of the implanted material were measured by AES sputter etching technique. The results exhibit that nitrogen implantation has no significant affection to the stress corrosion, but the chromium and erbium implantation has prolonged the incubation period of the stress corrosion cracking. (C) 1999 Kluwer Academic Publishers.

High-frequency hydrogen-related infrared modes in silicon grown in a hydrogen atmosphere

High-frequency vibrational modes have been observed at liquid-helium temperature in silicon samples grown in a H-2 or D-2 atmosphere. The highest-frequency ones are due to the overtones and combination modes of SiH fundamentals. Others are CH modes due to (C,H) complexes, but the simultaneous presence of NH modes due to (N,H) complexes cannot be excluded. The present results seem to show also the existence of centers including both SiH and CH or NH bonds. One sharp mode at 4349 cm-l is related to a weak SiH fundamental at 2210 cm(-1). The related center is ascribed to a vacancy fully decorated with hydrogen with a nearest-neighbor C atom. [S0163-1829(99)00911-X].

Characterization of strain relaxation in As ion implanted Si1-xGex epilayers grown by gas source molecular beam epitaxy

Strain relaxation in the As ion implanted Si0.57Ge0.43 epilayers was studied by double-crystal x-ray diffractometry and transmission electron microscopy, and was compared to that in the nonimplanted Si0.57Ge0.43 epilayers. Experimental results show that after rapid thermal annealing (RTA) the x-ray linewidth of the As+-implanted Si0.57Ge0.43 epilayers is narrower than that of the nonimplanted epilayers, and than that of the partially relaxed as-grown samples, which is due primarily to low density of misfit dislocations in the As+-implanted SiGe epilayers. RTA at higher than 950 degrees C results in the formation of misfit dislocations for the nonimplanted structures, and of combinations of dislocations and precipitates (tentatively identified as GeAs) for the As+-implanted epilayers. The results mean that the strain relaxation mechanism of the As+-implanted Si1-xGex epilayers may be different from that of the nonimplanted Si1-xGex epilayers. (C) 1998 American Institute of Physics.