Carbon Implantation Research Articles

Epitaxial 3C-SiC nanocrystal formation at the SiO2/Si interface after carbon implantation and subsequent annealing in CO atmosphere

3C-SiC nanocrystallites were epitaxially formed on a single crystalline Si surface covered by a 150nm thick SiO2 capping layer after low dose carbon implantation and subsequent high temperature annealing in CO atmosphere. Carbon implantation is used to introduce nucleation sites by forming silicon–carbon clusters at the SiO2/Si interface facilitating the growth of 3C-SiC nanocrystallites.

Early Outcomes of Pyrolytic Carbon Hemiarthroplasty for the Treatment of Trapezial-Metacarpal Arthritis

Pyrolytic carbon implants have been successfully used in the treatment of osteoarthritis of the metacarpophalangeal and proximal interphalangeal joints. Recently, pyrolytic carbon hemiarthroplasties have been proposed for the treatment of osteoarthritis of the trapezial-metacarpal (TM) joint of the thumb. We wished to review our short-term outcomes for this device in the treatment of TM arthritis. Fifty-four arthritic TM joints in 49 patients, with a mean age of 59 years, were treated with use of a pyrolytic carbon hemiarthroplasty procedure. Underlying diagnoses included osteoarthritis in 44 thumbs, rheumatoid arthritis in 8 thumbs, psoriatic arthritis in 1 thumb, and juvenile rheumatoid arthritis in 1 thumb. The patients were followed up clinically as well as radiologically for an average of 22 months postoperatively. The overall 22-month survival rate excluding scaphotrapezio-trapezoidal joint arthritis was 80% according to a Kaplan-Meier analysis. Ten metacarpal subluxations were observed. Seven of these cases were salvaged by increasing the depth of the trapezial cup. A total of 15 reoperations were required in this cohort. No complications were seen in the patients with inflammatory arthritis. Thirty-five patients were pain free at the latest follow-up, and 6 reported mild to occasional pain with repetitive activities. The overall satisfaction rate was 40 of 49 patients (81%). Grip strength recovered to 86% of that of the contralateral side. Apposition key and opposition pinch strength improved to 92% and 95%, respectively, of those of the contralateral hand. Pyrolytic carbon thumb arthroplasty may prove to be an acceptable option for the treatment of TM, although a high complication rate was observed in this early cohort, with many cases of subluxation attributed to the creation of a too shallow trapezial cup. Further comparative studies are warranted. Therapeutic IV.

Способы поверхностной обработки титановых биполярных пластин водородно-воздушных топливных элементов

The Work is devoted to the research of influence of superficial processings of bipolar plates (BP) on specific electric characteristics of fuel ce)(s (FC). Researches were conducted on plates on the basis of the titan. Two methods of processing BP are considered: electrochemical gilding and ionic implantation of carbon. In work short descriptions of the resulted technologies, and also a technique and results of experiments are presented. In work it is shown that as gilding, and ionic implantation carbon titanic BP electric characteristics FC improve. Relative reduction of ohmic resistance FC in comparison with "pure" titanic plates have constituted 1,8 for electrochemical gilding and 1,4 for ionic implantation.

Molecular dynamics simulations to explore the effect of chemical bonding in the keV bombardment of Si with C60, Ne60 and 12Ne60 projectiles

Depth profiling experiments using secondary ion spectrometry (SIMS) have shown effects that are characteristic to the pairing of the C60+ projectile with a Si target. Previous molecular dynamics simulations demonstrate that this unusual behavior is due to the fact that strong covalent bonds are formed between the C atoms in the projectile and the Si atoms in the target, which result in the implantation of carbon into the solid. The focus of this paper is to understand how the formation of chemical bonds affects the net sputtered yield. The results of molecular dynamics simulations of the keV bombardment of Si with C60, Ne60 and 12Ne60 at normal incidence are compared over a range of incident kinetic energies from 5 to 20keV. The net yields with Ne60 and 12Ne60 are significantly greater than with C60 at all incident kinetic energies, with 12Ne60 having the largest values. Application of the mesoscale energy deposition footprint (MEDF) model shows that the initial deposition of energy into the substrate is similar with all three projectiles. Snapshots of the initial pathway of the projectile atoms through the substrate show a similar lateral and vertical distribution that is centered in the region of the energy footprint. Therefore, the reason for the reduced yield with C60 is that the C atoms form bonds with the Si atoms, which causes them to remain in the substrate instead of being sputtered.

Laser emission in Nd:YVO4 channel waveguides at 1064 nm

In this work, we report 1064 nm laser emission in Nd:YVO4 channel waveguides fabricated by carbon implantation. Typical threshold pump powers (∼808 nm) were ≥45 mW. Maximum conversion efficiency was 11.5% (29.6% slope efficiency), and up to 9 mW of signal was delivered. Sample lengths of 4 mm were sufficient to completely absorb the pump power. The special spectral characteristics of this material such as broad absorption band and superior cross sections compared to the YAG crystal makes it suitable for developing compact sources to be integrated in optoelectronic devices.

NI (PT) SI Thermal Stability Improvement by Carbon Implantation

The thermal stability of Ni(Pt)-silicides by carbon implantation was evaluated. The Ni(Pt)-silicide morphology and phase formation were studied by means of sheet resistance (Rs) measurements, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) inspection, energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis. The substrate crystallinity, carbon implantation dose and energy and the anneal conditions determine the stability of the silicide. Platinum and carbon increase the phase stability of Ni-silicide at high temperatures by increasing the disilicide nucleation temperature. The dominant degradation mechanism is morphological degradation for the NiPtSi:C films whereas transition to the NiSi2 phase is the dominant degradation mechanism for NiSi:C films. As compared to carbon incorporation by epitaxial growth of Si:C, the carbon implant has the advantage of being a simple technique that can also be applied to pMOS devices.

Optimization of ClusterCarbon™ process parameters for strained Si lattice

We present here the substitutional carbon dependence of ClusterCarbon implant energy and dose, and anneal parameters such as solid phase epitaxial regrowth (SPER) temperature and various high temperature millisecond flash anneal conditions. With a multiple implant sequence of carbon implants one can obtain a fairly uniform carbon profile and we show that it provides better carbon substitution [C] sub when compared to a single implant. It is been established that optimizing the percentage of [C] sub requires an SPER anneal temperature <850 °C followed by a millisecond anneal. We show that carbon substitution increases with SPER temperature up to 800 °C and decreases beyond this temperature supporting the fact that carbon has a significant probability of being excited out of its substitutional site beyond 850 °C. We report here that SPER anneal with an additional millisecond flash anneal that provides highest carbon substitution, [C] subs > 2%. For a given millisecond anneal and for implants with various energies and doses we show that the percentages of [C] sub increases linearly with the fraction of carbon dopants within the amorphous layer.

Correlations between process parameters and film properties of diamond-like carbon films formed by hydrocarbon plasma immersion ion implantation

Plasma immersion ion implantation with hydrocarbon gases (HC-PIII) leads to both carbon implantation and carbon thin film deposition. The films are diamond-like carbon (DLC), mostly amorphous carbon with hydrogen (a-C:H). In the present review, examples from the literature on the deposition of HC-PIII DLC films are discussed. The process parameters of HC-PIII, including bias voltage, plasma-forming gas, and experimental setup, are correlated with the properties of the DLC film, such as bonding characteristics, hardness, stress state, and the resulting tribological performance, as shown in friction and wear tests.

Surface topography and morphology characterization of PIII irradiated silicon surface

The effect of plasma immersion ion implantation (PIII) treatment on silicon surfaces was investigated by micro-Raman and atomic force microscopy (AFM) technique. The surface damage was given by the implantation of carbon, nitrogen, oxygen and argon ions using an inductively coupled plasma (ICP) source at low pressure. AFM studies show that surface topography of the PIII treated silicon wafers depend on the physical and chemical nature of the implanted species. Micro-Raman spectra indicate that the significant reduction of intensity of Raman peak after PIII treatment. Plasma immersion ion implantation is a non-line-of-sight ion implantation method, which allows 3D treatment of materials. Therefore, PIII based surface modification and plasma immersion ion deposition (PIID) coatings are applied in a wide range of situations.

Silicon carbonitrides: On the attainability of stable compounds with high nitrogen content

Thin stoichiometric SiCN thin films and layers along selected tie lines of the phase diagram have been synthesized from the elements by means of ion implantation of carbon and nitrogen ions into silicon wafer substrates as well as rf magnetron cosputtering of targets with different Si∕C area ratios by using Ar∕N2 sputter gas with successive variation of the N2 content. After synthesis, the samples were heat treated under high vacuum conditions utilizing an electron beam annealing system. Resonant nuclear reaction analysis, non-Rutherford backscattering spectrometry and Auger electron spectroscopy have been used to perform an elemental analysis of the films and layers, respectively. The chemical binding states were investigated with x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy.

Evaluation of porous vitreous carbon or silicon implants by radiology in rat's skull

Evaluate by CT the use of porous vitreous carbon (PVC) and silicon (S) implants as the replacement bone in the craniofacial skeleton of rats. 40 rats divided in: Group A (n=20) PVC submitted to the implant of a fragment in skull. After the euthanasia, the animals were divided into two subgroups: A I: 10 animals, studied in the 7th postoperative day (P.O) and AII: 10 animals, studied in the 28th P.O. In group B, S, 20 rats were submitted to S implant in the skull. All other steps were identical to group A, with designation of subgroups BI and BII. CT with beams in axial cuts of 1 mm thickness to obtain 3-D information. It was used Hounsfield scale for evaluate the radio density of the implant. They were used non parametric tests to analyze the results. The 7th PO boss remained in the two groups, but for 28th PO, observed reduction in the volume of the implant in Group A, not observed in group B. CT studies noticed different radio densities around all of S prostheses (pseudo-capsule), that don't appeared in CPV implants. The S has remained unchanged in the CT, but the CPV has had a modification in its radio density (p< or = 0,05), in all implants. In CT evaluation the implants of CPV have greater deformation that the S, which makes them not suitable for replacement of membranous bone in the rat skull.

Carbon band implants in animal experiments. Light and transmission electron microscopy studies of biocompatibility

Part of the patella ligament was resected in rabbits and replaced by carbon fibre implants. After 1, 2, 3, 6 weeks, 3 and 12 months carbon implants with surrounding tissues as well as iliac lymph nodes were removed and examined by light- and transmission electron microscopy. Of special interest were the questions whether the carbon fibre implant, will be removed by phagocytosis and substituted by a new ligament or a adequate repair tissue? Our light- and transmission electron microscopic studies give no indication of successful removal of carbon fibres by phagocytosis. The carbon fibre implant was surrounded by dense connective tissue like a scar. In deep layers of the carbon implant was no vital dense or regular connective tissue, even not after 3 and 12 months. There is no replacement of the carbon fibre implant by a new ligament or tendon but a persistent foreign body reaction. With regard to these results it is very doubtful if good late results with ligament and tendon replacement by carbon fibre implants can be expected in patients.

Artifacts in the sputtering of inorganics by C 60n+

In the present study, the basic issues in C 60 n+ sputtering are studied using silicon, gold and platinum samples. Sputtering yields are measured for energies in the range of 5–30 keV, by sputtering micrometre sized craters on the surface of flat clean samples and measuring their volumes using atomic force microscopy (AFM). Net deposition of carbon occurs for all three materials at 5 keV, and is not specific to silicon which forms a carbide. The threshold energy for net sputtering is dependent on the sputtering yield and the stopping power of the substrate. Away from the threshold, the sputtering yields agree well with Sigmund and Claussen's thermal spike model after allowance for the sputtering of the deposited carbon atoms. AFM images show the formation of unusual surface topography around the transition region between sputtering and deposition. Analysis of the bottom of a crater using imaging SIMS shows a significant enhancement of carbon clusters as well as various silicon–carbon groups, indicating the importance of carbon deposition and implantation in a gradual mixed layer formed from sputtering. The thickness of this interface layer is shown to be approximately 5 nm.

Enhancement of surface properties of AISI 8620 by plasma immersion ion implantation

In this study, AISI 8620 steel samples were implanted with nitrogen using plasma immersion ion implantation (PIII) at 320, 380 or 450°C. In addition, PIII was used for simultaneous implantation of carbon and nitrogen into the steel at 380 or 450°C. Treated and untreated samples were studied by wear friction testing, microhardness measurement, atomic force microscopy, SEM study and glancing angle X-ray diffraction diagnosis. Experimental results indicated that the friction coefficient increased after PIII treatment and wear reduced by a factor of 4–60 for PIII treatment with pure nitrogen, although carbon + nitrogen coimplantation increased the wear rate.

Formation of planar waveguide in BiB3O6 crystal by MeV carbon implantation

Non-leaky planar waveguide structure has been fabricated in x-cut BiB3O6 crystal by 6MeV C3+ ion implantation at a dose of 1×1014ions/cm2. The effective refractive indices of the waveguide are measured at a wavelength of 632.8nm. We perform a computer code based on the finite difference method to reconstruct the refractive index profiles of nx and ny of this waveguide. The beam propagation method is used to calculate the electric and magnetic field profiles in the waveguide region from the reconstructed refractive index profiles. Our simulated data show that the refractive index increased waveguide layer can confine the mode completely.

Preliminary Results of Nonconstrained Pyrolytic Carbon Arthroplasty for Metacarpophalangeal Joint Arthritis

To review early outcomes of arthritic metacarpophalangeal (MCP) joints treated with nonconstrained pyrolytic carbon implants to evaluate efficacy, clinical outcomes, and durability. One hundred forty-two consecutive arthroplasties (61 patients) were retrospectively reviewed. Diagnoses included osteoarthritis (OA), traumatic arthritis, and inflammatory arthritis. One hundred thirty were primary joint replacements, and 12 were prior-silicone revisions. The average patient age was 55 years (range, 21-77 years); 36 patients were women and 25 were men. Average follow-up period was 17 months (range, 3-42 months), and 43 patients were followed up for a minimum of 1 year. For OA patients, according to the analog pain scale used, pain decreased from 73.0 to 8.5 of 100, functionality increased from 20.1 to 86.6 of 100, and appearance improved from 62.7 to 93.6 of 100. The rheumatoid arthritis (RA) group showed decreased pain from 43.1 to 8.9 of 100, functional improvement from 26.7 to 83.3 of 100, and increased appearance from 25.2 to 77.1 of 100. At 1 year, satisfaction was greater than 90% for both groups. Arc of motion for OA patients improved from 44 degrees to 58 degrees . Oppositional pinch increased 126%, and grip strength improved 40%. Rheumatoid arthritis patients increased their MCP joint motion arc from 32 degrees to 45 degrees . Oppositional pinch increased 89%, but grip strength decreased. Radiographs at 1 year demonstrated stable prostheses in all of the OA joints. The RA group overall demonstrated evidence of axial subsidence (10.5% of joints) and periprosthetic erosions (16.4% of joints). In RA joints with greater than 1-year follow-up period, 55.0% had axial subsidence, 95.0% had an increased radiolucent seam, and 45.0% had periprosthetic erosions. The overall implant survivorship is 141 joints to date. The overall minor complication rate was 6%, and major complication rate was 9%. Preliminary results suggest that pyrolytic carbon MCP joint arthroplasty provides good pain relief, patient satisfaction, and functional improvement in managing OA and select cases of RA. Longer follow-up evaluation will help validate these promising early results. Therapeutic IV.

Principal processes occurring at simultaneous bombardment of tungsten by carbon and deuterium ions

Simultaneous bombardment of tungsten with deuterium and carbon leads to both tungsten erosion and implantation of carbon and deuterium in the W surface. These processes have been studied experimentally by simultaneous bombardment of magnetron deposited W layers with D and C ions at energies in the keV range. The experimental results were compared to numerical simulations using the TRIDYN code. The key parameter separating steady-state W erosion from continuous growth of a C layer on the surface is the C fraction in the incident flux. The dynamical change of the surface composition with increasing fluence was monitored in situ by ion beam analysis. The experimental results are well reproduced by the TRIDYN simulations, which are based on a kinematic model of ion scattering in the target. Significant contributions by chemical effects outside the scope of the TRIDYN model can therefore be excluded. A negligible contribution of chemical effects is also supported by the measured concentrations of retained D, which are not sufficient to create a significant contribution of chemical reactions with carbon to implantation and sputtering. Surface roughness of the specimens was found to be the key parameter for the observed shift of the transition point from continuous C layer growth to steady-state tungsten erosion with increasing D fraction in the incident ions.

Optical Properties of KTaxNb1-xO3 Waveguides Formed by Carbon and Proton Implantation

Planar optical waveguides in KTaxNb1-xO3 (KTN) crystals were formed by 3.0 MeV C ion implantation with the dose of 1×1015 ions cm-2 and 500 keV proton implantation with the dose of 2×1016 ions cm-2, respectively. The modes in KTN waveguides were measured by a model 2010 prism coupler, four dark modes were observed at 633 nm, while only one mode was observed at 1539 nm for the waveguide formed by C ion implantation. Reflectivity calculation method (RCM) was applied to simulate the refractive index profile in waveguides. The SRIM'2006 (the Stopping and Range of Ions in Matter) code was applied for simulating the process of the ion implantation in order to obtain a better understanding for the waveguide formation.

Resurfacing Arthroplasty Versus Silicone Arthroplasty for Proximal Interphalangeal Joint Osteoarthritis

To compare the outcomes of silicone proximal interphalangeal joint (PIPJ) arthroplasties to pyrolytic carbon implants in patients with osteoarthritis. This study is a retrospective review of 41 arthroplasties in 22 patients with severe PIPJ osteoarthritis performed by a single surgeon. There were 13 patients and 22 joints in the silicone group with an average follow-up of 45 months. There were 9 patients and 19 joints in the pyrolytic carbon group with an average follow-up of 19 months. Clinical assessment included range of motion, grip strength, and deformity. Radiographs were evaluated for alignment, subsidence, and implant fracture. Patients filled out a subjective questionnaire with respect to pain, appearance of the finger, and satisfaction. Complications were recorded. In the silicone group, the average preoperative PIPJ range of motion (ROM) was 11 degrees /64 degrees (extension/flexion) and the average postoperative ROM was 13 degrees /62 degrees . In the pyrolytic carbon group, the average preoperative PIPJ ROM was 11 degrees /63 degrees and the average postoperative ROM was 13 degrees /66 degrees . Eleven of 20 joints in the silicone group and 4 of 19 joints in the pyrolytic carbon group had a coronal plane deformity as defined by angulation of the PIPJ > or =10 degrees . The average coronal plane deformity was 12 degrees in the silicone group and 2 degrees in the pyrolytic carbon group. The difference was statistically significant. In the silicone group, 3 of 22 joints required additional surgery. Two implants in one patient were removed and the PIPJ fused, and one implant was permanently removed for sepsis. In the pyrolytic carbon group, 8 of 19 joints squeaked, and there were 2 early postoperative dislocations and 2 implants with radiographic loosening. To date, there has been no revision surgery. Both groups had good pain relief. Patients were generally satisfied with the appearance of their joints in the pyrolytic carbon arm; however, satisfaction with appearance was variable in the silicone group. Nine of 13 patients in the silicone group and 6 of 7 patients in the pyrolytic carbon group would have the procedure again. Both implants provide excellent pain relief and comparable postoperative ROM. Complications were implant specific. The results of this series show promise for the pyrolytic carbon PIPJ resurfacing arthroplasty but did not clearly demonstrate superiority compared with the silicone implant.

Transition from tungsten erosion to carbon layer deposition with simultaneous bombardment of tungsten by helium and carbon

Simultaneous bombardment of tungsten layers with helium and carbon ions leads to both erosion of tungsten and implantation of carbon. The underlying processes have been investigated numerically and experimentally as a function of the carbon fraction in the incident ion flux for ion energies in the kilo electron volt range. Tungsten layers were deposited on polished single-crystal silicon substrate by magnetron sputter deposition to eliminate the influence of surface roughness on the experimental results. The fluence-dependent dynamics of the surface composition was measured in situ by ion beam analysis. The given projectile-target system is subject only to kinematic processes, and is therefore particularly suitable for benchmarking of purely kinematic simulations based on the binary-collision approximation, as implemented in the TRIDYN code. TRIDYN calculations match the experimental results very well, which demonstrates the validity of the kinematic description. In particular, the simulations allow us to predict the change of surface composition by bombardment with gaseous and nonvolatile ions, as well as the transition point from W erosion to C deposition as function of the carbon fraction in the incident ion flux.